Electrochemical energy storage devices

ABSTRACT

Integrated devices comprising integrated circuits and energy storage devices are described. Disclosed energy storage devices correspond to an all-solid-state construction, and do not include any gels, liquids, or other materials that are incompatible with microfabrication techniques. Disclosed energy storage device comprises energy storage cells with electrodes comprising metal-containing compositions, like metal oxides, metal nitrides, or metal hydrides, and a solid state electrolyte.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/827,054, (now U.S. Pat. No. 11,527,774) filed Mar. 23, 2020, which isa continuation-in-part of U.S. application Ser. No. 16/245,657 (now U.S.Pat. No. 10,601,074), filed Jan. 11, 2019, and a continuation-in-part ofU.S. application Ser. No. 16/295,983 (now U.S. Pat. No. 10,658,705),filed on Mar. 7, 2019. U.S. application Ser. No. 16/245,657 claims thebenefit of and priority to U.S. Provisional Application No. 61/502,797,filed on Jun. 29, 2011, and U.S. Provisional Application No. 62/639,602,filed on Mar. 7, 2018. U.S. application Ser. No. 16/245,657 is also acontinuation-in-part of U.S. application Ser. No. 15/818,494 (now U.S.Pat. No. 10,199,682), filed on Nov. 20, 2017, which is a continuation ofU.S. application Ser. No. 15/279,254 (now U.S. Pat. No. 9,853,325),filed on Sep. 28, 2016, which claims the benefit of U.S. ProvisionalApplication No. 62/233,785, filed on Sep. 28, 2015. U.S. applicationSer. No. 16/245,657 is also a continuation-in-part of U.S. applicationSer. No. 13/536,029 (now abandoned), filed on Jun. 28, 2012, whichclaims the benefit of and priority to U.S. Provisional Application No.61/502,797, filed on Jun. 29, 2011. U.S. application Ser. No. 16/295,983claims the benefit of and priority to U.S. Provisional Application No.62/639,602, filed on Mar. 7, 2018. Each of these applications are herebyincorporated by reference in their entireties.

FIELD

The present invention relates to energy storage devices having no closeprecedent in the prior art and methods for making energy storagedevices. The devices diverge from the prior art in their scale, physicalconstruction and geometry, chemistry, electrical behaviors, andapplications.

CONSTRAINTS ON THE PERFORMANCE OF THE CURRENT ART

Hundreds of developed battery chemistries and architectures exist, andthere is likewise an extreme diversity in terms of cycle life, storagecapacity, robustness, stability, and cost. Nevertheless, certaincommonalities emerge after careful consideration of the many variants.

Conventional batteries exhibit high energy densities compared to mostother methods of energy storage, but perform very poorly compared tocombustible sources of energy such as fossil fuels, alcohols, andhydrogen gas, all of which exceed conventional batteries by manymultiples in this regard. This has important implications with regard topowered portable devices and electric traction.

Conventional batteries have low power density compared to bothcapacitors and high velocity flywheels. Their ability to followfluctuating electrical loads and complex electrical impedances istherefore limited as well.

Some secondary batteries are based upon purportedly reversibleelectrochemical reactions, but they are not, in fact, fully reversiblein any practical sense. Secondary batteries characteristically losestorage capacity over time, and exhibit degradation of their componentparts as they undergo repeated charging and discharging. For example,secondary batteries may exhibit a loss in capacity due to destruction ofthe electrolyte, the anode, or the cathode. Overcharging and fullydischarging secondary batteries may also cause capacity loss. In extremecases, secondary batteries, such as lithium-based secondary batteries,may also exhibit a short circuit and rapidly discharge and heat and evencatch fire. Additionally, exposure of many secondary batteries toelevated temperatures may also degrade various components and result incapacity loss. Thus, secondary batteries, for the most part, cannot befully discharged without damage, degradation, and a considerableabbreviation of their useful working lives. Conversely, they cannottolerate overcharging.

Conventional batteries are subject to electrical leakage and chargedissipation and cannot maintain a given state of charge indefinitely oreven over a span of weeks. Such dissipation can eventually lead to fulldischarge and damage to the battery.

Conventional batteries cannot be charged instantaneously or evenparticularly quickly. Presenting conventional batteries with anexcessive charging current in an effort to accelerate the chargingprocess will generally damage the device. Moreover, charging with anyrapidity entails a complex charging algorithm and an intelligentinterface, increasing system complexity.

Conventional batteries, for the most part, are comprised of liquidsand/or gels, which do not lend themselves to precision manufacturing orextreme reductions in scale, and which may be subject to leakage and/orevaporation and may require external containment vessels.

Conventional batteries do not thrive in extreme temperatureenvironments. With the exception of the small subset of high temperaturebatteries, such as sodium sulfur and lithium sulfur types, almost nonecan endure temperatures of even a hundred degrees Celsius, whileoperation at zero degrees Celsius and below results in greatlydiminished capacity and sluggish performance.

Conventional batteries are low voltage devices, with about 4 voltsrepresenting the maximum operating potential of any establishedchemistry, and 2 volts or less being more representative. Such a voltagerange is impractically low for many applications, and thus batterymanufacturers must resort to connecting a number of individual cells inseries to achieve higher voltages. Balancing such series of cells can bedifficult due to normal cell-to-cell variation in electrical output.Individual cell failure can also result in lost capacity and diminishedusability.

Most of the established conventional battery chemistries appear to beapproaching the ends of their respective development cycles and havebeen subject to diminishing returns in terms of performanceimprovements.

Such deficiencies are attributable both to the chemistries themselves,the design and articulation of the electrodes and their interface withthe electrolyte material, and with the way that traditional fabricationtechniques have tended to dictate architecture.

SUMMARY

Devices for storing energy at a high density are described. Methods ofmaking energy storage devices are also described. In embodiments, theenergy storage devices correspond to an all solid-state construction,and do not include any gels, liquids, or other materials that areincompatible with microfabrication techniques, such as may be used inthe fabrication of integrated circuits and photovoltaic devices. Energystorage devices described herein include batteries and other Faradaicsolid-state energy storage devices, such as devices that store (or arecapable of storing upon charging) electrical energy by way of reversibleelectrochemical redox reactions taking place at electrodes of thedevices.

In a first aspect, an energy storage device embodiment comprises a firstelectrode, a solid electrolyte positioned in direct contact with thefirst electrode, and a second electrode positioned in direct contactwith the solid electrolyte. It will be appreciated that the first andsecond electrodes may be positioned such that the solid electrolyte isbetween the first and second electrodes. The electrodes may includeactive materials that directly take part in electrochemical or Faradaicredox reactions, such as metals and metal oxides.

Various aspects of the electrodes may take on different configurations,depending on the particular embodiments utilized. For example, in someembodiments, a variety of electrode thicknesses are useful with theenergy storage devices. For example, in embodiments, the first electrodeand the second electrode independently have thicknesses selected betweenabout 1 nm and about 5 nm, between about 1 nm and about 10 nm, betweenabout 1 nm and about 15 nm, between about 1 nm and about 20 nm, betweenabout 1 nm and about 25 nm, between about 1 nm and about 30 nm, betweenabout 1 nm and about 35 nm, between about 1 nm and about 40 nm, betweenabout 1 nm and about 45 nm, between about 1 nm and about 50 nm, betweenabout 1 nm and about 55 nm, between about 1 nm and about 60 nm, betweenabout 1 nm and about 65 nm, between about 1 nm and about 70 nm, betweenabout 1 nm and about 75 nm, or between about 1 nm and about 80 nm.Optionally, an electrode thickness is about 5 nm, about 10 nm, about 15nm, about 20 nm, about 25 nm, about 30 nm, about 35 nm, about 40 nm,about 45 nm, about 50 nm, about 55 nm, about 60 nm, about 65 nm, about70 nm, about 75 nm, about 80 nm, about 85 nm, about 95 nm, or about 100nm. It will be appreciated, however, that electrodes of any thicknessgreater than or about 1 nm may be utilized for some embodiments, such asup to 1 μm, or greater.

In some embodiments, the electrodes may have independent chemicalstructures. For example, the first electrode and the second electrodeindependently comprise metal containing compositions. Example metalcontaining compositions include, but are not limited to, metal oxides,metal hydrides, metal sulfides, metal nitrides, metal halides, metalcomposites, intermetallic compounds, metalloid alloys, or metalliccompositions, such as base metals or alloys. Example metals in metalcontaining compositions include transition metals and specifically oneor more of Mn, Zn, Fe, Co, Ni, Cu, Mo, Tc, Ru, V, Bi, Ti, Rh, Pd, Ag,Au, W, Re, Os, La, Na, K, Rb, Cs, Ir, or Pt. In some embodiments, anelectrode comprises the same metal and/or metal containing compositionas another electrode. In other embodiments, an electrode comprises adifferent metal and/or metal containing compositions as anotherelectrode. Optionally, an electrode comprises a metal, metal oxide, ametalloid, and/or a metalloid alloy (i.e., a composition including ametal and a metalloid). Example metalloids include boron, silicon,germanium, arsenic, antimony, carbon, aluminum, and selenium.Optionally, electrodes comprise alternating layers of active materialand another material, such as amorphous carbon.

In some embodiments, using particular metal containing compositions forthe electrodes may be advantageous, as certain metals and metalcontaining compositions may exhibit desirable properties. Variousexamples are contemplated, depending on the particular chemistryinvolved with the energy storage device. For example, in an energystorage device based on oxygen, an electrode comprising a metal oxide,such as nickel cobaltite, zinc nickel cobalt ternary oxide, tungstenoxide, tungsten trioxide, iridium oxide, rhodium oxide, palladium oxide,and other metals and metal oxide as described herein, may be capable ofundergoing reversible redox reactions to gain or lose oxygen atomsduring charging or discharging. As another example, in some embodiments,an electrode comprising a metal may be capable of forming sequences ofmetal oxides of progressively greater molecular weight at a respectiveelectrode surface, such as by way of different redox reactions.

Working ions other than oxygen may be used. For example, in an energystorage device based on sulfur, such as where a sulfur ion is a workingion, an electrode comprising a metal sulfide, such as molybdenumdisulfide, titanium disulfide, Li₁₀GeP₂S₁₂, Li₆PS₅Cl, Li₇P₃S₁₁, orcobalt sulfide, may be capable of undergoing reversible redox reactionsto gain or lose sulfur atoms during charging or discharging. In anenergy storage device based on nitrogen, such as where a nitrogen ion isa working ion, an electrode comprising a metal nitride, such as titaniumnitride, cobalt nitride, nickel nitride, may be capable of undergoingreversible redox reactions to gain or lose sulfur atoms during chargingor discharging. In an energy storage device based on chlorine, such aswhere a chloride ion is a working ion, an electrode comprising a metalchloride or metal hypochlorite, such as CoCl₂, VCl₃, BiCl₃, FeOCl, orBiOCl, may be capable of undergoing reversible redox reactions to gainor lose chlorine atoms during charging or discharging. In an energystorage device based on iodine, such as where an iodide ion is a workingion, an electrode comprising a metal iodide or metal hypoiodite, such asCoI₂, VI₃, BiI₃, FeOI, or BiOI, may be capable of undergoing reversibleredox reactions to gain or lose iodine atoms during charging ordischarging. In an energy storage device based on fluorine, such aswhere a fluoride ion is a working ion, an electrode comprising a metalfluoride, such as LaF₃, may be capable of undergoing reversible redoxreactions to gain or lose fluorine atoms during charging or discharging.In an energy storage device based on a non-lithium alkali metal, such aswhere an alkali metal ion is a working ion, an electrode comprising anon-lithium alkali metal may be capable of undergoing reversible redoxreactions to gain or lose alkali metal atoms during charging ordischarging. In an energy storage device based on hydrogen, such aswhere a hydrogen ion (e.g. a proton, H⁺) is a working ion, an electrodecomprising a metal hydride may be capable of undergoing reversible redoxreactions to gain or lose hydrogen atoms or may facilitate redoxreactions involving hydrogen containing compounds (e.g., H₂O) duringcharging or discharging.

In some embodiments, appropriate pairing of electrodes may beadvantageous. In one embodiment, a solid-state energy storage device mayinclude the same metal containing composition in each electrode. Forexample, upon charging, one electrode will include an increase in theamount of metal in the higher oxidation state, while the oppositeelectrode will have an increase in the amount of metal in the loweroxidation state.

For example, iron may be progressively oxidized to form a range ofoxides of different oxidation states. In some embodiments, iron may bepresent in the form of fine granules, such as in a sintered compact,which may aid in the formation of a progression of oxidation states.Metallic iron may be oxidized first to iron +2 (iron II) and thenfurther to iron +3 (iron III). Oxidation of metallic iron to iron +2 maybe associated with the formation of iron II oxide (FeO). As the iron(II) oxide is oxidized further to form iron +3, additional oxygen may betaken up and the iron may take the form of Fe₃O₄, corresponding to amixture of both iron +2 and iron +3. Further oxidation may result inhigher and higher amounts of iron (III), where the iron may begin toadopt the configuration of iron III oxide (Fe₂O₃). Further oxidationand/or reduction may occur. Since each oxidation state is associatedwith a different potential relative to the metallic state, charging theelectrode may require different potentials to drive eachoxidation/reduction reaction. Consequently, during discharging of theelectrode, the opposite is true, and discharging may begin occurring atone potential and then change to a different potential as amounts of themetal change to a different oxidation state.

Optionally, an electrode undergoes oxygen adsorption during charging ofthe solid-state energy storage device, such as by way of an oxidation orreduction reaction. Optionally, an electrode undergoes oxygen desorptionduring charging of the solid-state energy storage device, such as by wayof an oxidation or reduction reaction. Optionally, a metal of anelectrode exhibits a work function of between about 4 eV and about 5 eV.

In some embodiments, the metal containing composition of an electrode isdispersed on an electrically conductive supporting matrix. For example,in embodiments, the electrically conductive supporting matrix maycomprise carbon black, carbon nanotubes, graphite, or other materialsthat may provide electrical conductivity while also providing a platformfor deposition of the electrode material. In embodiments, use of anelectrically conductive supporting matrix may be advantageous forincreasing a surface area of the metal containing composition of theelectrode to increase the electrode mass that may take part in redoxreactions when charging and/or discharging the energy storage devices.Optionally, the electrodes may include conductive materials, such ascarbon black, carbon nanotubes, and graphite. Use of carbon nanotubes asconductive matrices or conductive materials for the electrodes may beparticularly advantageous. For example, in some embodiments, packing ofan active material of an electrode (such as a metal containingcomposition) in carbon nanotubes or a carbon nanotube matrix may resultin an increased capacity for an energy storage device using theelectrode, even though the volumetric amount of active material may beless than in an electrode comprising the active material in a pure form.For example, by packing nickel oxide in carbon nanotubes, a storagecapacity of an electrode may be increased by up to 800 farad per gram.

Optionally, electrodes may comprise a mixture of multiple metals ormetal containing compositions. Such a mixture may correspond to an alloyor a mixture of metal oxides, metal sulfides, metal nitrides, metalchlorides, metal hydrides, etc. By combining multiple metals, anincrease in certain properties (e.g., capacity, conductivity) may berealized. For example, a combination of cobalt oxide and nickel oxide,such as may be referred to as nickel cobaltite, may correspond to amaterial that exhibits an electrical conductivity greater than eithernickel oxide or cobalt oxide taken alone. Such an increase in electricalconductivity may be up to 100×-500× greater than the individual oxides.

Optionally, electrodes may be independently fabricated usingcontrollable deposition methods. Useful deposition techniques include,but are not limited to, atomic layer deposition, magnetron sputtering,spin deposition, thermal evaporation, and chemical vapor deposition.Other fabrication techniques useful for fabricating the electrodes mayinclude or involve other techniques, such as ultraviolet lithography,x-ray lithography, holographic lithography, laser ablation, and thermalevaporation.

Optionally, electrodes may exhibit or comprise a layered construction.For example, an electrode may include a first layer of an activematerial, such as a metal containing composition, a second layer of aconductive material (e.g., carbon, graphite, carbon nanotubes), and athird layer of the active material. The electrode may further includeadditional pairs of layers of conductive material and active material inalternating fashion. For example, in an embodiment, an electrodecomprises a 10 nm layer of electrode active material (e.g., metalcontaining composition, as described above), a 5 nm layer of amorphouscarbon, and a 10 nm layer of the electrode active material. Theelectrode materials may also be patterned using conventional patterningtechniques known in the art of microfabrication, including masking,lift-off, etching, etc. to generate a desired electrode layout.

Various aspects of the solid electrolyte may take on differentconfigurations, depending on the particular embodiments utilized. Forexample, in some embodiments, a variety of electrolyte thicknesses areuseful with the disclosed energy storage devices. For example, anelectrolyte optionally has a thickness selected between about 1 nm andabout 5 nm, between about 1 nm and about 10 nm, between about 1 nm andabout 20 nm, between about 1 nm and about 50 nm, between about 1 nm andabout 100 nm, between about 1 nm and about 150 nm, between about 1 nmand about 200 nm, between about 1 nm and about 250 nm, between about 1nm and about 300 nm, between about 1 nm and about 350 nm, between about1 nm and about 400 nm, between about 1 nm and about 450 nm, betweenabout 1 nm and about 500 nm, between about 1 nm and about 550 nm, orbetween about 1 nm and about 600 nm. Specific example electrolytethicknesses include 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm,160 nm, 170 nm, 180 nm, 190 nm, 200 nm, 210 nm, 220 nm, 230 nm, 240 nm,250 nm, 260 nm, 270 nm, 280 nm, 290 nm, 300 nm, 310 nm, 320 nm, 330 nm,340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm, 400 nm, 410 nm, 420 nm,430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, 500 nm, 510 nm,520 nm, 530 nm, 540 nm, 550 nm, 560 nm, 570 nm, 580 nm, 590 nm, and 600nm. Other electrolyte thicknesses may be useful for some embodiments,though electrolyte thicknesses less than or about 250 nm may beadvantageous for certain embodiments.

As the electrolyte thickness is increased, embodiments may experiencereduced device performance. For example, depending on the energy storagedevice chemistry and/or working ion, an electrolyte thickness maycorrelate, at least in part, with the ionic conductivity of theelectrolyte. At some particular thickness, however, the electrolyte mayexhibit a dramatic change in ionic conductivity, making such anelectrolyte unsuitable for use in an energy storage device. For example,depending on the particular electrolyte composition used in someembodiments, the maximum useful electrolyte thickness may be about 500nm, about 550 nm, about 600 nm, about 650 nm, or less than about 700 nm.Each particular electrolyte composition may exhibit a “cut-off”thickness value above which the electrolyte exhibits conductivityproperties comparable to the bulk, such as where an ionic conductivityis unsuitable for use in an energy storage device, and below which theelectrolyte exhibits conductivity properties different from the bulk,such as where the ionic conductivity is about 10× greater or more, about100× greater or more, about 1000× greater or more, about 10000× greateror more, or about 100000× greater or more than the ionic conductivity ofthe electrolyte in the bulk. In some embodiments, a solid electrolyteexhibits an ionic conductivity at about 25° C. that is about 1000 timesgreater or more than a bulk ionic conductivity for the solidelectrolyte. Optionally, the bulk ionic conductivity for the solidelectrolyte corresponds to a conductivity of ions at about 25° C. forthe solid electrolyte having a thickness greater than about 700 nm. Toprovide advantageous performance, at about 25° C., the solid electrolyteoptionally exhibits an ionic conductivity selected from about 0.000001S·cm⁻¹ to about 0.2 S·cm⁻¹, or optionally exhibits an ionic conductivityin excess of about 0.00001 S·cm⁻¹ at about 25° C. Optionally, the solidelectrolyte exhibits, at about 25° C., an ionic conductivity selectedfrom about 0.00001 S·cm⁻¹ to about 0.15 S·cm⁻¹, selected from about0.0001 S·cm⁻¹ to about 0.1 S·cm⁻¹, selected from about 0.001 S·cm⁻¹ toabout 0.05 S·cm⁻¹. It will be appreciated that the electricalconductivity of the solid electrolyte, at about 25° C. will be verysmall, such as from about 10⁻²⁵ S·cm⁻¹ to about 10⁻⁶ S·cm⁻¹, from about10⁻²⁵ S·cm⁻¹ to about 10⁻⁷ S·cm⁻¹, from about 10⁻²⁵ S·cm⁻¹ to about 10⁻⁸S·cm⁻¹, from about 10⁻²⁵ S·cm⁻¹ to about 10⁻⁹ S·cm⁻¹, from about 10⁻²⁵S·cm⁻¹ to about 10⁻¹⁰ S·cm⁻¹, from about 10⁻²⁵ S·cm⁻¹ to about 10⁻¹¹S·cm⁻¹, from about 10⁻²⁵ S·cm⁻¹ to about 10⁻¹² S·cm⁻¹, or smaller still.

In embodiments, the solid electrolyte allows for migration of ionsacross the solid electrolyte, making the solid electrolyte suitable foruse in an energy storage device. It will be appreciated that certainsolid electrolyte materials may exhibit ionic conductivity properties athigh temperatures, such as at temperatures of about 600° C., but theionic conductivity decreases with temperature such that the solidelectrolyte material is not ionically conductive at low temperatures,such as temperatures of 25° C. or even 50° C. Advantageous electrolytesfor energy storage devices of the invention, however, maintain suitableionic conductivity properties even at temperatures at which conventionalbatteries are useful, such between 0° C. and about 50° C., such as about25° C. Unlike conventional batteries, the energy storage devices of theinvention exhibit suitable properties at most temperatures commonlyencountered by humans. For example, the solid-state electrolytes used inthe energy storage devices may exhibit suitable ionic properties attemperatures as low as about −50° C., as well as at temperatures as highas about 50° C. and higher.

Useful electrolytes may be dependent on the chemistry of the energystorage device. For example, in energy storage devices based on oxygen(i.e., where a working ion is an oxygen ion), the electrolyte may beionically conductive for oxygen ions (e.g., O⁻, O⁺, O²⁻). Similarly, inenergy storage devices based on sulfur (i.e., where a working ion is asulfur ion), the electrolyte may be ionically conductive for sulfur ions(e.g., S⁻S⁻², S⁺, etc.). As another example, in energy storage devicesbased on a halogen (i.e., where a working ion is a chloride ion,fluoride ion, or iodide ion), the electrolyte may be ionicallyconductive for halogen ions (i.e., F⁻, Cl⁻, I⁻). As another example, inenergy storage devices based on nitrogen (i.e., where a working ion is anitrogen ion), the electrolyte may be ionically conductive for nitrogenions (e.g., N⁻, N⁺, N²⁻, etc.). As another example, in energy storagedevices based on a non-lithium alkali metal (i.e., where a working ionis a non-lithium alkali metal ion), the electrolyte may be ionicallyconductive for alkali metal ions (e.g., Na⁺, K⁺, Rb⁺, Cs⁺). As anotherexample, in energy storage devices based on hydrogen (i.e., where aworking ion is a hydrogen ion), the electrolyte may be ionicallyconductive for protons or hydride ions.

Various compositions are useful for the solid electrolytes of the energystorage devices. For example, in embodiments, a solid electrolytecomprises a ceramic. Optionally, the ceramic is selected from the groupincluding a perovskite ceramic, a ceramic having a perovskite structure,a zirconium ceramic, a zirconium-scandia ceramic, a ceria-gadoliniaceramic, an alumina ceramic, or any combination of these. Optionally,yttria stabilized zirconia, which is useful on its own as anelectrolyte, may optionally be combined with other materials, such aslanthanum silicon oxygen compounds (e.g., lanthanum silicon oxyapatite(LSO)), which may also be used on its own as an electrolyte. Usefulelectrolyte compositions also include gadolinia doped cerium dioxide.Other doped cerium dioxide (ceria) compositions are useful aselectrolytes. For example, ceria may be doped with one or morecompositions including, but not limited to, CaO, SrO, MgO, BaO, yttria,and samarium. A variety of other compositions are useful aselectrolytes, including doped lanthanum gallate (LaGaO₃), bismuthoxides, and strontium doped lanthanum oxides. Other lanthanum basedmaterials are also useful as electrolytes, including La₂Mo₂O₉ (LAMOX).

Other examples of solid electrolytes include, doped ceria oxides, dopedlanthanum gallate (LaGaO₃), strontium doped lanthanum oxides, bariumzirconate, cerium pyrophosphate, SrCeO₃, BaCeO₃, LaNbO₄, LaCrO₃, YSZ,alkaline solid state electrolytes, iron fluoride, copper fluoride,alkali metal doped alumina, and solid-state fast ion conductingelectrolytes, such as silver iodide, or rubidium silver iodide. It willbe appreciated that oxides, zirconates, pyrophosphates and relatedelectrolytes are useful, in embodiments, for conducting oxygen ionsand/or sulfur ions. Alkaline electrolytes are optionally useful forconducting nitrogen ions. Doped alumina electrolytes are optionallyuseful for conducting non-lithium alkali metal ions. Iron fluoride,copper fluoride, and solid-state fast ion conducting electrolytes areoptionally useful for conducting halide ions. Barium zirconate, ceriumpyrophosphate, SrCeO₃, BaCeO₃, LaNbO₄, and/or LaCrO₃ are optionallyuseful for conducting protons.

Optionally, a solid electrolyte comprises a crystalline ceramic, such asa single crystalline or polycrystalline ceramic material. In someembodiments, a solid electrolyte optionally comprises an amorphousmaterial, such as an amorphous ceramic material.

Optionally, the solid electrolyte comprises a composite solidelectrolyte including a plurality of different ceramics. For example thesolid electrolyte may comprise layers of different ceramic materials. Inembodiments, strained solid electrolytes may exhibit higher ionicconductivities than unstrained solid electrolytes and, thus, impartingstrain on a solid electrolyte may provide for a way to increase theionic conductivity of the solid electrolyte to a level suitable for usein a solid-state energy storage device. In embodiments, introducingstress or strain into the electrolyte may result in the generation ofvoids or other defects, such as crystallographic defects. Use ofcomposite solid electrolytes may be useful, in embodiments, to impartstrain or stress on the solid electrolyte materials, as different solidelectrolyte materials may exhibit different thermal expansionproperties. In embodiments, the solid electrolytes may be formed at hightemperatures and then allowed to relax to ambient temperature, where thedifferent thermal expansion properties of different materials may createlevels of strain that allow the solid electrolyte to possess an ionicconductivity suitable for use in an energy storage device. The stress orstrain placed on the electrolyte may, in embodiments, modify the ionicconductivity of the electrolyte to increase it to a level beyond that inthe unstressed or unstrained condition. Other techniques may be usefulfor imparting stress or strain to an electrolyte, including exploitingdifferent thermal expansion characteristics of non-electrolyte materialspositioned proximal to, adjacent to, or in direct contact with theelectrolyte.

Additionally, piezoelectric materials may optionally be positionedproximal to, adjacent to, or in direct contact with the electrolyte andexposed to a potential to cause expansion or contraction of the materialto impart stress or strain on an electrolyte. In some embodiments, useof piezoelectric materials may be beneficial for controlling the amountof ionic conductivity permitted by the electrolyte. For example, anenergy storage device may include a solid electrolyte, in someembodiments, which has a relatively low ionic conductivity and apiezoelectric material that is positioned proximal the electrolyte inorder to control the ionic conductivity of the electrolyte, as desired.For example, in some embodiments, the piezoelectric material may beactuated to afford an increase in the electrolyte ionic conductivityduring a charging or discharging cycle, but then be de-actuated orrelaxed while not charging or discharging. Such an embodiment, forexample, may provide a way to prevent or reduce self-discharge of anenergy storage device while not in use or while in storage.

In some embodiments, a solid electrolyte comprises or exhibits astructure, such as a crystal structure, including voids or defects, suchas crystallographic defects, that permit conduction or migration of ionsthrough the solid electrolyte at temperatures between about 0° C. andabout 100° C. It will be appreciated that operation at temperaturesbetween about 0° C. and about 50° C. is especially desirable, but theelectrolytes may permit operation at temperatures above thesetemperatures, including above 100° C. In some embodiments, the solidelectrolyte comprises or exhibits a structure including voids or defectsthat also permit conduction or migration of ions through the solidelectrolyte at temperatures outside of the previously mentioned range,such as at temperatures less than about 0° C. or greater than about 100°C. As described above, it will be appreciated that this property may becontrasted with the same material of the solid electrolyte in the bulk,where voids and defects that are present in the bulk material may stillnot provide for suitable ionic conductivity, since the overall thicknessof the material in bulk may provide an effect that reduces ionicconductivity. Optionally, the defects correspond to one or more vacancydefects, interstitial defects, boundary defects, line defects, planardefects, bulk defects, or lattice imperfections.

Optionally, a solid electrolyte comprises a doped ceramic including oneor more dopants. Useful dopants include, but are not limited to, analkali metal dopant, an alkaline earth dopant, a group 3 dopant, ascandium dopant, a yttrium dopant, a lanthanide dopant, a titanium oxidedopant, a hydrogen dopant, a silver dopant, a lead dopant, a calciadopant, a magnesia dopant, a dysprosia dopant, or a ytterbia dopant.Optionally, a solid electrolyte comprises a heavily doped ceramic. Forexample, in some embodiments a solid electrolyte comprises a ceramicalloy, such as beta alumina. Doping a ceramic may advantageouslyintroduce defects that modify an ionic conductivity as compared to theundoped ceramic.

Optionally, the solid electrolyte comprises an amorphous structure, isin an amorphous state, or is an amorphous solid. An amorphous structure,as used herein, refers to an arrangement of component atoms that lackthe long-range order present in crystalline materials. In embodiments,an amorphous structure may still exhibit some short-range order, whichmay arise due to the material's stoichiometry and the chemical bondingbetween the atoms that make up the material. In some embodiments, thematerial comprising a solid electrolyte may be an electrical insulator(i.e., have a low electrical conductivity for transmission of electrons)when present in one state, such as amorphous state or a single crystalstate, but may be an electrical conductor (i.e., have a higherelectrical conductivity for transmission of electrons) when present inanother state, such as a polycrystalline state, even though thedifferent states comprises the same stoichiometry and short-rangearrangement of bonded atoms. In some cases, a polycrystalline solidelectrolyte, in contrast, may have an electrical conductivitycharacteristic of or approaching that of a conductor. Accordingly, thecrystal structure of the solid electrolyte may impact the rate ofself-discharge of a device including the solid electrolyte between twoelectrodes, where stored energy is transported across the electricallyconductive solid electrolyte by migration of electrons from oneelectrode to the other across the electrolyte, rather than through anexternal load, as is typically the case when the device is discharged.It will be appreciated that solid electrolytes in an amorphous state maybe electrical insulators or otherwise exhibit a relatively lowelectrical conductivity and yet still exhibit significant ionicconductivity, permitting their advantageous use as an electrolyte.

Without wishing to be bound by any theory, the ionic conductivitytransport mechanism may arise through defects or voids present in theamorphous structure that effectively allow migration of ions across theelectrolyte. The ionic conductivity transport mechanism may also oralternatively arise through the ability of the amorphous structure toaccommodate incorporation of ions from one region of the structure and acorresponding release of ions from another region of the structure.Again without wishing to be bound by any theory, the electricalconductivity transport mechanism, in contrast, may arise throughtransfer of electrons along crystal grain boundaries. As the number ofgrain boundaries are limited in a single crystal material, electronconductivity may be relatively low. In a polycrystalline material, whichhas many grain boundaries, the electron conductivity may be relativelyhigh. In an amorphous material, no grain boundaries may be presentbecause the material may not have a regular crystal structure, and thusthe primary electron transport mechanism (i.e., along grain boundaries)may be suppressed. It will be appreciated that formation of amorphoussolid electrolytes may be achieved through careful control of thefabrication conditions, such as deposition rate, temperature, pressure,etc.

Optionally, solid electrolytes may be fabricated using a controllabledeposition method. Useful deposition techniques include, but are notlimited to, atomic layer deposition, magnetron sputtering, spindeposition, thermal evaporation, and chemical vapor deposition. Otherfabrication techniques useful for fabricating the electrolytes mayinclude or involve other techniques, such as ultraviolet lithography,x-ray lithography, holographic lithography, laser ablation, and thermalevaporation. The electrolyte may also be patterned using conventionalpatterning techniques known in the art of microfabrication, includingmasking, lift-off, etching, etc. to generate a desired electrolytelayout.

Optionally, formation of the solid electrolyte in an amorphous state mayoccur by carefully controlling the deposition conditions, such astemperature, pressure, precursor selection, and the like. For example,the solid electrolyte may be deposited at a relatively low temperatureto maintain formation of an amorphous structure. In embodiments,deposition at temperatures too high may result in formation of apolycrystalline electrolyte structure. Example deposition temperaturesfor deposition of the solid electrolyte in an amorphous state are at orabout 100° C., 110° C., 120° C., 130° C., 140° C., 150° C., 160° C.,170° C., 180° C., 190° C., 200° C., 210° C., 220° C., 230° C., 240° C.,or 250° C., between 0° C. and 300° C., between 0° C. and 250° C.,between 50° C. and 250° C., between 100° C. and 250° C., between 150° C.and 250° C., or between 200° C. and 250° C.

To maintain the amorphous character of the electrolyte, an electrodethat is deposited over the amorphous electrolyte optionally may occur bycarefully controlling the deposition conditions, such as temperature,pressure, precursor selection, and the like. For example, the electrodemay optionally be deposited at a relatively low temperature. Exampledeposition temperatures for the electrode are at or about 100° C., 110°C., 120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180° C., 190°C., 200° C., 210° C., 220° C., 230° C., 240° C., or 250° C., between 0°C. and 250° C., between 50° C. and 250° C., between 100° C. and 250° C.,between 150° C. and 250° C., or between 200° C. and 250° C.

Optionally, deposition of an electrode over an amorphous electrolyte maytake place in multiple deposition sub-steps, such as where anelectrolyte is subjected consecutive exposures of metal containingorganic precursors, optionally with additional oxidation and/orreduction sub-steps, to allow dissociated chemisorption, combustion, andreduction to take place. Optionally, following and/or prior to eachexposure of organic precursors, the electrolyte and in-process electrodebeing deposited may need to be cleaned in order for further amounts ofthe metal to be efficiently deposited, as residual precursors andreaction products may inhibit further deposition. Example cleaningagents include water and ozone. Details of a low temperature atomiclayer deposition can be found in Elam et al., Chem. Mater., 2015, 27(14), 4950-4956, (DOI: 10.1021/acs.chemmater.5b00818), which is herebyincorporated by reference. Without wishing to be bound by any theory, itis believed that deposition of the electrode over an amorphouselectrolyte may result in damage to or crystallization of theelectrolyte material if not performed carefully. For example, bycontrolling the temperature or other conditions of the electrodedeposition, the integrity of the amorphous structure of the electrolytecan be maintained.

It will be appreciated that the solid electrolytes useful with theenergy storage devices disclosed herein are different from those used inconventional batteries. For example, in embodiments, the solidelectrolyte is actually solid and is free from or does not include anyliquids or gels. Additionally, the solid electrolytes are categoricallydifferent from those used with lithium-based batteries. For example,lithium-based batteries may rely on a lithium containing electrolyte,such as a lithium salt dissolved in a liquid electrolyte. Inembodiments, the solid electrolytes used with the energy storage devicesdescribed here are free from or do not include any lithium, such aslithium atoms, lithium ions, or lithium salts. The solid electrolytesuseful with the energy storage devices disclosed herein are alsodifferent from those used in other devices, such as solid oxide fuelcells. Some electrolytes, in the bulk, may be ionically conductive athigh temperatures, such as temperatures in excess of 500° C., but maybehave as ionically non-conductive at low temperatures, such as 0°C.-100° C. The electrolytes useful herein, however, exhibit high ionicconductivity at low temperatures, and this effect may arise by way ofthe size (i.e., thickness) of the electrolyte. Thicker electrolytes ofthe same material may not behave in the same way or exhibit the sameproperties.

Optionally, an energy storage device further comprises a second solidelectrolyte positioned in direct contact with the second electrode, anda third electrode positioned in direct contact with the second solidelectrolyte. Optionally, an energy storage device further comprises oneor more solid electrolyte and metal oxide electrode bi-layers positionedin direct contact with a topmost electrode. It will be appreciated thatthe characteristics described above may also apply to the additionalsolid electrolytes and electrodes.

Other configurations for the energy storage devices described herein arecontemplated, including those making use of hydrogen ions as a workingion. In a specific embodiment a solid-state energy storage devicecomprises an oxygen absorbing solid-state material; a first electrode ingaseous communication with the oxygen absorbing solid-state material,such as a first electrode that comprises a transition metal ortransition metal alloy and has a structure that accommodates water; asolid-state electrolyte positioned adjacent to the first electrode, suchas a solid-state electrolyte that comprises a ceramic material andconducts protons at temperatures of about 25° C.; and a second electrodepositioned adjacent to the solid-state electrolyte, such as a secondelectrode that comprises a metal, a metal hydride, or both. Optionally,the second electrode comprises one or more of ruthenium, platinum,palladium, magnesium and/or carbon nanotubes. Optionally, the firstelectrode has a thickness selected from 1 nm to 100 nm. Optionally, thesolid-state electrolyte has a thickness selected from 1 nm to 500 nm.Optionally, at about 25° C., the solid-state electrolyte exhibits aproton conductivity selected from about 0.000001 S·cm⁻¹ to about 0.2S·cm⁻¹. Optionally, the first electrode comprises an oxide of the metalor metal alloy, such as nickel cobaltite. Optionally, the energy storagedevice is coated with or bounded by a gas impermeable material, whichmay be useful, for example, to prevent ingress or egress of gaseousoxygen.

In some cases, oxygen gas may be evolved at one or more electrodesduring use of an energy storage device described herein. In some cases,an amount of oxygen atoms in the energy storage device, such as in oneor more electrodes, may be limiting, and so it may be desirable toprovide a source of oxygen to one or more electrodes. Accordingly, itmay be advantageous to provide oxygen to an electrode in the form ofoxygen gas. Optionally, an energy storage device may comprise an oxygenabsorbing solid-state material in contact with or in gaseouscommunication with one or more electrodes and/or with a solidelectrolyte. For example, an oxygen absorbing solid-state material maybe useful for containing any evolved oxygen gas. As another example, anoxygen absorbing solid-state material may be useful as a source ofoxygen. Thus by implementing one or more electrodes in contact with orin gaseous communication with oxygen absorbing solid-state material orby implementing one or more electrodes as composite electrodes includinga transition metal and/or transition metal oxide and an oxygen absorbingsolid-state material, the evolution or take-up of oxygen may beaccommodated.

Useful oxygen absorbing solid-state materials comprises cobalt, a cobaltsalt, cerium, and/or ceria. Optionally, a resistive heating element isprovided in thermal communication with the oxygen absorbing solid-statematerial. Optionally, the oxygen absorbing solid-state material absorbsoxygen when a pressure of oxygen is increased. Optionally, the oxygenabsorbing solid-state material releases oxygen when a pressure of oxygenis decreased. In some cases, the oxygen absorbing solid-state materialmay be positioned in thermal communication with a heat source or a heatsink to allow for control over a temperature of the oxygen absorbingsolid-state material, which may further be useful for controlling therelease or absorption of oxygen. Although the above discussion focuseson oxygen, other gases may be substituted for oxygen, such as nitrogen,or hydrogen.

Optionally, a solid-state energy storage device further comprises afirst current collector in electrical contact with the first electrode;and a second current collector in electrical contact with the secondelectrode. Optionally, the first current collector and the secondcurrent collector each independently comprise a compliant porous carbonmaterial. Optionally, first current collector and the second currentcollector each independently have thicknesses selected from 1 nm to 50nm. Optionally, the first current collector and the second currentcollector each independently provide electrical communication with anexternal circuit. Optionally, the first current collector and the secondcurrent collector each independently accommodate expansion andcontraction of materials of the solid-state energy storage device, suchas the electrodes, the electrolyte, and other materials of thesolid-state energy storage device. Optionally, the first currentcollector provides active sites for ionizing oxygen.

In embodiments, the energy storage devices may be charged using anysuitable voltage. For example, charging voltages may be higher than usedin conventional secondary batteries. For example, in embodiments, avoltage difference between the first electrode and the second electrodemay be greater than or about 0.5 V, greater than or about 1 V, greaterthan or about 2 V, greater than or about 4 V, greater than or about 8 V,greater than or about 16 V, or between 0.5 V and 20 V. Other voltagedifferences are possible, including voltages of about 0.5 V, about 1 V,about 1.5 V, about 2 V, about 2.5 V, about 3 V, about 3.5 V, about 4 V,about 4.5 V, about 5 V, about 5.5 V, about 6 V, about 6.5 V, about 7 V,about 7.5 V, about 8 V, about 8.5 V, about 9 V, about 9.5 V, about 10 V,about 10.5 V, about 11 V, about 11.5 V, about 12 V, about 12.5 V, about13 V, about 13.5 V, about 14 V, about 14.5 V, about 15 V, about 15.5 V,about 16 V, about 16.5 V, about 17 V, about 17.5 V, about 18 V, about18.5 V, about 19 V, about 19.5 V, about 20 V, between 0.5 V and 1 V,between 1 V and 1.5 V, between 1.5 V and 2 V, between 2 V and 2.5 V,between 2.5 V and 3 V, between 3 V and 3.5 V, between 3.5 V and 4 V,between 4 V and 4.5 V, between 4.5 V and 5 V, between 5 V and 5.5 V,between 5.5 V and 6 V, between 6 V and 6.5 V etc., between 6.5 V and 7V, between 7 V and 7.5 V, between 7.5 V and 8 V, between 8 V and 8.5 V,between 8.5 V and 9 V, between 9 V and 9.5 V, between 9.5 V and 10 V,etc.

In embodiments, the solid-state energy storage devices may becharacterized by electrical energy densities comparable to other energystorage devices, such as conventional batteries, and may even exceed theenergy storage densities of conventional batteries. For example, theelectrical energy density of the solid-state energy storage device maybe greater than or about 10 J/cm³, greater than or about 20 J/cm³,greater than or about 50 J/cm³, greater than or about 100 J/cm³, greaterthan or about 150 J/cm³, greater than or about 200 J/cm³, greater thanor about 250 J/cm³, greater than or about 300 J/cm³, greater than orabout 350 J/cm³, greater than or about 400 J/cm³, greater than or about450 J/cm³, greater than or about 500 J/cm³, greater than or about 1000J/cm³, greater than or about 5000 J/cm³, greater than or about 10000J/cm³, greater than or about 50000 J/cm³, or selected from 10 J/cm³ to50000 J/cm³, such as from 10 J/cm³ to 50 J/cm³, from 50 J/cm³ to 100J/cm³, from 100 J/cm³ to 500 J/cm³, from 500 J/cm³ to 1000 J/cm³, from1000 J/cm³ to 5000 J/cm³, from 5000 J/cm³ to 10000 J/cm³, or from 10000J/cm³ to 50000 J/cm³.

In contrast to conventional batteries, the disclosed energy storagedevices may be included in an integrated circuit, microelectromechanicalsystem, or other system assembled using microfabrication tools. Forexample, in embodiments, the first electrode, the solid-stateelectrolyte, and the second electrode are components of an integratedcircuit. Optionally, one or more circuit elements of the integratedcircuit are positioned in electrical communication with the firstelectrode or the second electrode such that the one or more circuitelements receive electrical energy stored by the solid-state energystorage device. It will be appreciated that electrical communication maybe direct or indirect (e.g., with one or more intervening elements).

In addition, the disclosed energy storage devices may be included as acomponent of a photovoltaic system. For example, in embodiments, thefirst electrode, the solid-state electrolyte, and the second electrodeare integrated with a photovoltaic cell or are integrated components ofa photovoltaic system. For example, in some embodiments, the firstelectrode, the solid-state electrolyte, and the second electrode may bedeposited on a substrate that comprises a component of a photovoltaiccell. It will be appreciated that various fabrication processes may beadvantageously used for preparation of an energy storage device includedas a component of a photovoltaic system, such as atomic layerdeposition, magnetron sputtering, spin deposition, chemical vapordeposition, and thermal evaporation. The deposition of variouscomponents of energy storage device may optionally be performed at aboutthe same time or subsequent to construction of any electrodes needed orused by the photovoltaic cell. In embodiments, electrodes of aphotovoltaic cell are positioned in electrical communication with thefirst electrode and the second electrode such that electrical energygenerated by the photovoltaic cell may be used to charge the energystorage device for storage therein or so that electrical energy storedby the solid-state energy storage device may be utilized as needed inplace of photovoltaic output.

In embodiments, the energy storage device may comprise a component of aphotovoltaic output management system. Advantageously, the energystorage device may optionally store electrical power generated by aphotovoltaic system in excess of that consumed by a load otherwisepowered by the photovoltaic system, which may occur, for example, duringtimes of peak power production or low demand. In some embodiments, theenergy stored by the energy storage devices may be useful for smoothingthe output variability of a photovoltaic system over time and may forexample, be useful for maintaining a substantially constant or lessvariable output from the photovoltaic system as energy productionchanges from moment to moment (e.g. due to a passing cloud).Additionally, the stored energy may optionally be provided to and usedby a load connected to the photovoltaic system when the photovoltaicenergy production is lower than that required by the load, such asduring times of high demand, or during night or on cloudy days. In thisway, the energy storage device may enhance the utility of a photovoltaicsystem by allowing storage of excess energy when generated, use ofstored energy when insufficient generation occurs, and maintainingsubstantially constant output as photovoltaic power is modulated.

In another aspect, methods of making energy storage devices aredisclosed. In embodiments, methods of this aspect comprise depositing afirst electrode on or over a substrate, such as by using a firstcontrollable deposition method, depositing a solid electrolyte on orover the first electrode, such as by using a second controllabledeposition method, and depositing a second electrode on or over thesolid electrolyte such as by using a third controllable depositionmethod. Optionally, additional electrolyte and electrode depositionprocesses may be included in the method in order to generate energystorage devices exhibiting a stacked multilayer configuration.Optionally, electrolyte and electrode layers may be prepared in aninterdigitated configuration.

Useful controllable deposition methods include, but are not limited to,those involving atomic layer deposition, magnetron sputtering, chemicalvapor deposition, spin deposition, ultraviolet lithography, x-raylithography, holographic lithography, laser ablation, and thermalevaporation. As described above, deposition conditions, such astemperature, pressure, precursor selection, and the like, may becarefully controlled to achieve particular characteristics of theelectrode and/or electrolyte materials. For example, the deposition mayoccur at a relatively low temperature, such as to form and/or maintainan amorphous structure in an electrolyte. Example depositiontemperatures for deposition of the solid electrolyte include about 100°C., 110° C., 120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180°C., 190° C., 200° C., 210° C., 220° C., 230° C., 240° C., or 250° C.,between 0° C. and 250° C., between 50° C. and 250° C., between 100° C.and 250° C., between 150° C. and 250° C., or between 200° C. and 250° C.

Optionally, the deposition of the electrodes generates electrodes of adesired thickness, as described above. For example, in embodiments, adeposited electrode thickness is selected from about 1 nm to about 80nm.

Optionally, the deposited solid electrolyte comprises one or more of aperovskite ceramic, a ceramic having a perovskite structure, a zirconiumceramic, a ceria-gadolinia ceramic, an alumina ceramic, and anycombination of these. Optionally, the deposited solid electrolytecomprises one or more of a perovskite ceramic, a ceramic having aperovskite structure, a zirconium-scandia ceramic, a ceria-gadoliniaceramic, an alumina ceramic, and any combination of these. Optionally,the deposition of the solid electrolyte generates an electrolyte of adesired thickness, as described above. For example, in embodiments, thesolid electrolyte has a thickness selected from about 1 nm to about 1000nm, such as from 1 nm to 2.5 nm, from 2.5 nm to 5 nm, from 5 nm to 10nm, from 10 nm to 25 nm, from 25 nm to 50 nm, from 50 nm to 100 nm, from100 nm to 250 nm, from 250 nm to 500 nm, or from 500 nm to 1000 nm. Inembodiments, the solid electrolyte comprises or exhibits a structureincluding voids or defects that permit conduction or migration of oxygenions through the solid electrolyte at least at temperatures betweenabout 0° C. and about 100° C. Optionally, the solid electrolytecomprises or exhibits a structure including voids or defects that alsopermit conduction or migration of oxygen ions through the solidelectrolyte at temperatures less than about 0° C. or greater than about100° C. Other compositions for the electrolytes, as described herein,may optionally be used.

As described above, the solid-state energy storage devices may beincorporated in an integrated circuit. In embodiments, the substrate onwhich an electrode is deposited comprises a component of an integratedcircuit.

In some embodiments, methods of this aspect may include charging and/ordischarging an energy storage device. For example, a voltage differencemay be applied between the first electrode and a second electrode, suchas a charging voltage, in order to charge the energy storage device. Itwill be appreciated that, in embodiments, the charging may occur rapidlyor substantially instantaneously, such as within a period of seconds orminutes or a fraction thereof, depending on the current available fromthe voltage source and resistive losses between the voltage source andthe electrodes. This rapid charging may also occur, in embodiments,without damaging the electrodes or electrolyte. This may contrast withthe charging rate of a conventional battery, which may be limited by thekinetics taking place at the battery electrodes or within theelectrolyte, or may be limited because charging at a greater rate mayresult in damage to the structure of the battery, such as electrodedamage or electrolyte damage, and accompanying capacity loss. Inembodiments, the oxidation/reduction reactions that occur when chargingor discharging the energy storage devices occur at or near the electrodesurfaces and so the reactions may occur substantially quickly ascompared to, for example, intercalation processes or electroplatingprocesses that may occur in conventional batteries. High charge ordischarge rates may also or alternatively be aided by the small sizedimensions used in the energy storage devices, where only a smallphysical spacing between electrodes exists, allowing ionic migrationbetween the electrodes to occur rapidly. In embodiments, discharging mayoccur rapidly or substantially instantaneously, such as within a periodof seconds or minutes or a fraction thereof. This rapid discharging mayalso occur, in embodiments, without damaging the electrodes orelectrolyte. In embodiments, a discharge rate may be dictated by theresistance of a load applied between the electrodes of the energystorage devices and/or resistive losses between the load and theelectrodes. In embodiments, the energy storage devices may be chargedand/or discharged at rates of about C/20, about C/10, about C/5, aboutC/2, about 1 C, about 2 C, about 5 C or about 10 C or more withoutinducing damage to the energy storage device, such as damagecharacteristic of capacity loss, electrolyte oxidation or reduction,electrode destruction, etc. Charging times may also vary depending oncharging voltage, charging current, etc. Example charging times may beless than about 1 second, less than about 10 seconds, less than about 30seconds, less than about 1 minute, less than about 5 minutes, less thanabout 10 minutes, less than about 30 minutes, between 1 second and 60minutes, etc. Beneficially, energy storage device embodiments may bedischarged to zero charge stored or zero voltage difference betweenelectrodes without inducing damage to the energy storage device, such asdamage characteristic of capacity loss, electrolyte oxidation orreduction, electrode destruction, etc.

Further, in some embodiments, the energy storage devices exhibitexceptional cycle lives. For example, the energy storage devices may becharged and discharged any number of times without inducing damage tothe energy storage device, such as damage characteristic of capacityloss, electrolyte oxidation or reduction, electrode destruction, etc.For example, the energy storage devices of some embodiments may becharged and discharged more than or about 100 times, more than or about1000 times, more than or about 10000 times, more than or about 100000times, or more than or about 1000000 times, or between 1 and 1000000without damaging the energy storage device, such as damagecharacteristic of capacity loss, electrolyte oxidation or reduction,electrode destruction, etc.

Without wishing to be bound by any particular theory, there can bediscussion herein of beliefs or understandings of underlying principlesrelating to the invention. It is recognized that regardless of theultimate correctness of any mechanistic explanation or hypothesis, anembodiment of the invention can nonetheless be operative and useful.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides a plot illustrating the relationship of ionicconductivity and temperature for a variety of solid-state electrolytesin the bulk.

FIG. 2A provides a schematic overview of charging a solid-state energystorage device and FIG. 2B provides a schematic overview of discharginga solid-state energy storage device.

FIG. 3 provides a schematic illustration of processes taking placewithin a solid-state energy storage device.

FIG. 4 provides a schematic overview of processes taking place duringcharging and discharging of a solid-state energy storage device.

FIG. 5A and FIG. 5B provide overviews of processes for makingsolid-state energy storage devices.

FIG. 6 provides a schematic illustration of the crystal structure of asolid electrolyte, in accordance with some embodiments.

FIG. 7 provides a schematic illustration of the crystal structure of asolid electrolyte, in accordance with some embodiments.

FIG. 8 provides a schematic illustration of a system including energystorage devices distributed throughout an integrated circuit.

FIG. 9A, FIG. 9B, and FIG. 9C provide schematic illustrations of exampleenergy storage devices.

FIG. 10A and FIG. 10B provide schematic cross-sectional illustrations ofcomponents of example energy storage devices.

FIG. 11 provides a schematic cross-sectional illustration of anintegrated circuit including multilayer energy storage devices.

FIG. 12A and FIG. 12B provides schematic cross-sectional illustrationsof an photovoltaic device including multilayer energy storage devices.

DETAILED DESCRIPTION

The present application provides energy storage devices, such asFaradaic solid-state energy storage devices, and methods of making thesedevices. The devices are based on a unique architecture involving a pairof metal containing electrodes with a solid-state electrolyte (alsoreferred to herein as a solid electrolyte) positioned in between theelectrodes. For example, the metal containing electrodes may correspondto certain transition metals. For example, the solid-state electrolytemay correspond to certain ceramics capable of conducting ions throughtheir structure at an appreciable rate.

Advantageously, energy storage device embodiments may be of an entirelysolid-state construction. For example, all electrically active layersmay also provide structural functions, such that the energy storagedevice is not only entirely self-supporting but capable of reinforcingother elements to which it is conjoined.

As used herein, the term “Faradaic energy storage device” refers to adevice that stores energy electrochemically by way of reversibleoxidation and reduction reactions that take place at and with activematerials of electrodes of the device. The term “Faradaic energy storagedevice” may be interchangeable with the terms “battery” and“electrochemical cell” in some embodiments, and contrasts with otherenergy storage devices that do not involve bond-forming oxidation andreduction reactions involving the active material of the electrodes,such as supercapacitors.

FIG. 1 provides details of the ionic conductivity of a number ofsolid-state ceramic materials in the bulk. It will be appreciated thatthe ionic conductivity of most of these materials only reachesappreciable values at temperatures exceeding about 300° C. At roomtemperature, the ionic conductivity values of these ceramic materialsare extremely small, making them very effective ionic insulatingmaterials.

The inventors have discovered, however, that thin films of certainsolid-state materials, such as films having thickness of less than about700 nm, in some embodiments, may be engineered to exhibit high ionicconductivity at room temperature. This property allows the solid-stateceramics to function as electrolyte materials, which permitstransmission of ions. Such observation is entirely contrary to theelectrical behavior of the solid-state ceramics in the bulk describedabove.

The conduction of ions through the solid-state electrolyte provides thebasis for charge storage in some embodiments disclosed herein. FIG. 2Aand FIG. 2B provides schematic overviews of charging (FIG. 2A) anddischarging (FIG. 2B) of an example solid-state energy storage device200. Here, solid-state energy storage device 200 includes a firstelectrode 210, an electrolyte 220, and a second electrode 230. As shownin FIG. 2A, during a charging operation, anions may be driven from thefirst electrode 210, through the electrolyte 220, to second electrode230, while cations may be driven from the second electrode 230, throughthe electrolyte 220, to first electrode 210. As shown in FIG. 2B, duringa discharging operation, cations may be driven from first electrode 210,through the electrolyte 220, to second electrode 230, while anions maybe driven from the second electrode 230, through the electrolyte 220, tofirst electrode 210. It will be appreciated that in some embodimentsonly a single anionic species may correspond to the working ion, whilein other embodiments only a single cationic species may correspond tothe working ion. Embodiments are contemplated, however, where multipleionic species are the working ions, such as multiple anionic species,multiple cationic species, or combinations of anionic species andcationic species. Such identities will be established by the specificchemistry utilized in a specific energy storage device. It will beappreciated that, although FIGS. 2A and 2B depict simultaneoustransmission of both cations and anions, in practice ions tend to flowin one direction only during charging or discharging and that FIGS. 2Aand 2B are intended to cover each of the potential configurations, i.e.,where anions or cations are the working ions.

As depicted in FIG. 2A, during charging, electrons may be provided by avoltage source 240 to the first electrode 210. In embodiments whereoxygen anions (O⁻ or O²⁻) correspond to the working ion, the electronsmay be used in a reduction reaction at the first electrode where oxygenanions may be released. The oxygen anions may be conducted through thesolid electrolyte 220 to the second electrode 230, where they may betaken up by the second electrode and electrons may be released to thevoltage source in an oxidation reaction. It will be appreciated that theenergy required for the redox reactions, provided by the voltage source,may correspond, at least in part, to the energy stored in, at, or by theelectrodes. Other energy storage mechanisms may also contribute to theenergy stored by the system, including capacitive energy storage and/orinductive energy storage. Physical/chemical changes to the electrodesmay be observed during charging. For example, in embodiments, the firstelectrode 210 will undergo loss of oxygen atoms and the second electrode230 will undergo gain of oxygen atoms during charging. As anotherexample, the first electrode 210 and/or second electrode 230 mayphysically change size during charging.

FIG. 2B depicts discharging of the solid-state energy storage device200. The stored energy may be used during discharging by a load 250. Inembodiments where oxygen anions (O⁻ or O²⁻) correspond to the workingion, the electrons passed through the load 250 may be used in areduction reaction at the second electrode where oxygen anions may bereleased. The oxygen anions may be conducted through the solidelectrolyte 220 to the second electrode 230, where they may be taken upby the second electrode and electrons may be released to the voltagesource in an oxidation reaction. It will be appreciated that the energyused by the load may correspond, at least in part, to energy stored bythe electrodes, but other energy storage mechanisms may also contribute,such as capacitive energy storage and/or inductive energy storage.Physical/chemical changes to the electrodes may also be observed duringdischarging. For example, in one embodiment, the first electrode 210will undergo gain of oxygen atoms and the second electrode 230 willundergo loss of oxygen atoms during discharging. As another example, thefirst electrode 210 and/or second electrode 230 may physically changesize during discharging.

FIG. 3 provides a schematic overview of charging and discharging of anenergy storage device where oxygen anions correspond to the working ion.The energy storage device of FIG. 3 includes a first electrode 310, asolid electrolyte 320, and a second electrode 330. As illustrated firstelectrode 310 includes an oxide (M1O_(A)) of a first metal, M1, andsecond electrode 330 includes an oxide (M2O_(B)) of a second metal M2.It will be appreciated that the two metals may be the same or differentand the levels of oxygen present in the different electrodes may also bethe same or different.

Additionally, each electrode optionally includes a conductive supportingmatrix, in which the metals are distributed. In some embodiments, theconductive supporting matrix may correspond to a carbonaceous material,such as carbon black, graphite, carbon nanotubes, etc., for example.Inclusion of a conductive supporting matrix may be useful for increasinga usable surface area of an electrode. In some embodiments, only a thinlayer of the electrode may take part in oxidation/reduction reactions,and so increasing the surface area of the electrode may allow for anincrease in the overall amount of the electrode that may take part inthe reactions. In some cases, the conductive supporting matrix may allowfor improved interaction between the active electrode materials and theelectrolyte as compared to embodiments lacking the conductive supportingmatrix. Optionally, the conductive supporting matrix may function, atleast in part, as a current collector or provide electricalcommunication with a separate current collector.

In the uncharged configuration, bound oxygen atoms may be included inthe first electrode 310, the solid electrolyte 320, and the secondelectrode 330. During charging, however, some of the oxygen atoms maybecome unbound, such as due to the addition of electrons to the firstelectrode 310, where the oxygen atoms may become free ions, such asoxygen anions (O⁻ or O²⁻). These oxygen anions may move from firstelectrode 310 into the solid electrolyte 320. Oxygen ions added to thesolid electrolyte 320 may migrate through the solid electrolyte 320 andpass to the second electrode 330. In some circumstances, the oxygenanions added to the solid electrolyte 320 may become bound in thestructure of the solid electrolyte 320 and a different oxygen atom maybe released from the structure of the solid electrolyte 320 as an oxygenanion, creating an effective migration of the oxygen anion through thesolid electrolyte. The oxygen ions that are added to the secondelectrode 330 may be incorporated into the structure of the secondelectrode 330. In some cases, in the uncharged configuration the amountsof oxygen in the first electrode 310 and the second electrode 330 arethe same.

In the charged configuration, the amounts of oxygen in the firstelectrode 310 and the second electrode 330 may be different from that inthe uncharged configuration. As illustrated, after charging the firstelectrode 310 may have fewer oxygen atoms included in the structure, ascompared to the structure of the first electrode 310 in the unchargedstate. Similarly, as illustrated, after charging the second electrode330 may have more oxygen atoms included in the structure, as compared tothe structure of the first electrode 330 in the uncharged state. Thus,the first electrode 310 is illustrated as having a formula of M1O_(A+Δ),while the second electrode is illustrated as having a formula M₂O_(A-Δ).In some cases, in the charged configuration the amounts of oxygen in thefirst electrode 310 and the second electrode 330 are different.

During discharging, the opposite migration of oxygen occurs. Some of theoxygen atoms in the second electrode 330 may become unbound, such as dueto the addition of electrons, and the unbound oxygen atoms may becomeoxygen anions. These oxygen anions may move from third electrode 330into the solid electrolyte 320. Oxygen ions added to the solidelectrolyte 320 may migrate through the solid electrolyte 320 and passto the first electrode 310. The oxygen ions that are added to the firstelectrode 310 may be reincorporated into the structure of the firstelectrode 310.

In one example, a solid-state energy storage device comprises a firstelectrode including iron oxide, a solid-state oxygen ion conductingelectrolyte, and a second electrode including iron oxide. For example,the device may be formed using a symmetric configuration of iron oxidein the form of mixed iron +2 and iron +3 (Fe₃O₄, magnetite). Duringcharging, an amount of the iron +3 in one electrode may be reduced toiron +2, forming FeO. In the other electrode, an amount of the +2 ironmay be oxidized to +3 iron, forming Fe₂O₃. Looking at half reactions,the first electrode undergoes the reaction Fe₃O₄→3FeO+O²⁻+2e⁻, and thesecond electrode undergoes the reaction 2Fe₃O₄+O²⁻+2e⁻→>3 Fe₂O₃. Overallthe reaction is 3Fe₃O₄→3FeO+3Fe₂O₃.

Further oxidation may optionally occur to form higher oxides. As anexample, iron +3 may be oxidized to iron +4. Such an oxidation may takeplace where there is excess Fe₃O₄ in the opposite electrode. For thiscase, one half reaction is Fe₃O₄→3FeO+O²⁻+2e⁻. The other half reactionis Fe₂O₃+O²⁻+2e⁻→2FeO₂. Overall the reaction is Fe₃O₄+Fe₂O₃→3FeO+2FeO₂.It will be appreciated that the oxidation of iron from +3 to +4 mayoccur at a greater potential than the oxidation of iron from +2 to +3.

Advantageously, for certain embodiments, each electrode may be used asan anode or a cathode, depending on a charging configuration used wheninitially charging the energy storage devices. For example, a first ofthe two electrodes may be connected to a negative terminal of a voltagesource and a second of the two electrodes may be connected to a positiveterminal of the voltage source during charging of the energy storagedevice. After charging, the first electrode may function as an anode andthe second electrode may function as the cathode. Upon discharging, theenergy storage device may be recharged in the opposite configuration,i.e., where the first electrode may be connected to the positiveterminal of the voltage source and the second electrode may be connectedto the negative terminal of the voltage source. After this chargingcycle, the first electrode may function as the cathode and the secondelectrode may function as the anode.

This advantageous configuration may be achieved, in embodiments, by thecharge storage mechanism and the chemistry involved. For example, inembodiments, the electrodes may comprise an oxide of the same metal,though levels of oxidation of each of the electrodes may be differentand may change during charging and discharging. For example, in aspecific embodiment, the electrodes may both comprise an iron oxide.Other examples are possible, including where different metals or metaloxides comprise the different electrodes.

As noted above, in some embodiments, only a small layer of the electrodeproximal to the electrolyte may experience significant changes inoxidation state. For example, ions may be driven to or be obtained fromshallow depths in the electrodes, in some embodiments, such as a few nm.Accordingly, it may be desirable to form the electrodes as thin aspractical so as not to include excess electrode material that isincapable of taking part in oxidation/reduction reactions. Thus, in someembodiments, the electrode thickness may range from about 1 nm to about10 nm, about 1 nm to about 15 nm, from about 1 nm to about 20 nm, about1 nm to about 25 nm, from about 1 nm to about 30 nm, about 1 nm to about35 nm, from about 1 nm to about 40 nm, about 1 nm to about 45 nm, fromabout 1 nm to about 50 nm, about 1 nm to about 55 nm, from about 1 nm toabout 60 nm, about 1 nm to about 65 nm, from about 1 nm to about 70 nm,about 1 nm to about 75 nm, or about 1 nm to about 80 nm. In embodiments,the energy storage devices can operate using electrodes of anythickness, including electrodes thicker than about 75 nm or 80 nm, butas noted above, such thicknesses may not be the most efficient use ofthe electrode material and may contribute weight to the energy storagedevice while not contributing to the energy storage capacity.

Advantageously, the disclosed energy storage devices may operate under avariety of different voltage regimes. For example, an initial chargingoperation may correspond to a first reduction of metal in an anode suchthat anions are released by the anode to the solid electrolyte. Theanions may take part in a reaction at the cathode where anions areadsorbed or otherwise taken up by the cathode to participate in anoxidation. The cathode will thus be in a more oxidized state aftercharging. If sufficient ions are available, oxidation may take ondifferent levels as more and more of the ionic material is driven intothe cathode during charging.

Use of certain metals in the cathode may benefit from this increasedoxidation, as some metal species are capable of exhibiting differentoxidation states. In the case of iron, for example, iron atoms exhibitoxidation states of +1, +2, +3, +4, +5, and +6, though the oxidationstates of +2 and +3 may be the most common. If the electrode comprisesFe and oxygen is the working ion, a first charging stage may result increation in the cathode of FeO at a first charging voltage. As the FeObecomes saturated with oxygen, a second charging stage may occur, wherethe FeO becomes further oxidized to form Fe₂O₃. This process maycontinue, with the creation of Fe₃O₄, Fe₅O₆, Fe₆O₇, etc., each formed atincreasing charging voltages. It will be appreciated that iron is usedhere for illustrative purposes and that other metals, such as Mn, Zn,Fe, Co, Ni, Cu, Mo, Tc, Ru, V, Bi, Ti, Rh, Pd, Ag, Au, W, Re, Os, La,Na, K, Rb, Cs, Ir, and/or Pt, may be alternatively used in theelectrodes, though the principal of the operation of the energy storagedevice by creation of different oxides at increasing voltages may beapplicable. Table 1 and Table 2 respectively summarize different halfreactions that may take place during charging and discharging in someembodiments. It will be appreciate that while Tables 1 and 2 makereference to reactions involving O⁻ ions and single electrons (e⁻),parallel reactions may take place involving O²⁻ ions and a pairs ofelectrons (O²⁻) and other ionic species (nitrogen ions, sulfur ions,chloride ions, and hydrogen ions) may be substituted.

It will be appreciated that this increasing oxidation mechanism mayallow the energy storage devices, in embodiments, to be charged to highvoltages, such as where the charged voltage corresponds to a voltagedifference between a voltage of a first electrode and a voltage of asecond electrode proximal where a single solid electrolyte is positionedbetween the first and second electrodes. Such charging voltages may beconsiderably higher than allowed by previous battery chemistries. Forexample, in embodiments, the energy storage devices may be charged to avoltage between about 0 V and about 0.5 V, between about 0 V and about 1V, between about 0 V and about 1.5 V, between about 0 V and about 2 V,between about 0 V and about 2.5 V, between about 0 V and about 3 V,between about 0 V and about 3.5 V, between about 0 V and about 4 V,between about 0 V and about 4.5 V, between about 0 V and about 5 V,between about 0 V and about 5.5 V, between about 0 V and about 6 V,between about 0 V and about 6.5 V, between about 0 V and about 7 V,between about 0 V and about 7.5 V, between about 0 V and about 8 V,between about 0 V and about 8.5 V, between about 0 V and about 9 V,between about 0 V and about 9.5 V, or between about 0 V and about 10 V.In some embodiments, the energy storage devices may be charged to avoltage greater than about 5 V, greater than about 10 V, greater thanabout 15 V, or greater than about 20 V. It will be appreciated that, insome embodiments, as higher and higher voltages are encountered, anelectrical discharge may occur between electrodes and through the solidelectrolyte, resulting in loss of stored charge and potential damage tothe devices.

As another example, FIG. 4 provides a schematic overview of asolid-state energy storage device 400 making use of hydrogen ions(protons, H⁺) as the working ion. The configuration depicted in FIG. 4is not to scale and is provided as an example to facilitate descriptionof the general structure processes taking place. A first electrode 405is in contact with a solid electrolyte 410, which is in contact with asecond electrode 415. Second electrode 415 is exemplified as including ametal hydride (MH₂) and solid electrolyte 410 is exemplified as a protonconducting ceramic. First electrode 405 is exemplified as a compositestructure including a water accommodating transition metal oxide activematerial and a gas storage structure, such as a gas-absorbingsolid-state material. Optionally, the gas storage structure may flankand/or be in gaseous communication with the solid electrolyte 410 forproviding gas to interstices within a crystalline structure of the solidelectrolyte 410. For example, the gas storage structure may be orcomprise an oxygen absorbing solid-state material, such as an O₂ spongematerial. For example, the water accommodating transition metal oxideactive material may be in gaseous communication or contact with the O₂sponge material. It will be appreciated that the O₂ sponge material maytake up oxygen gas generated during charging of the energy storagedevice 400 and may provide oxygen gas as needed during discharging ofthe energy storage device 400. Example O₂ sponge materials include, butare not limited to, cobalt-, cobalt salt-, cerium-, and ceria-basedoxygen absorbing materials, such as strontium cobaltite, and [{(bpbp)Co₂^(II)(NO₃)}₂(NH₂bdc)](NO₃)₂.H₂O, where “bpbp” is2,6-bis(N,N-bis(2-pyridylmethyl)-aminomethyl)-4-tert-butylphenolato, and“NH₂bdc” is 2-amino-1,4-benzenedicarboxylato. See, for example, Chem.Sci., 2014, 5, 4017-4025 (DOI:10.1039/C4SC01636J), hereby incorporatedby reference, which describes crystalline salts of a series of cationicmultimetallic cobalt complexes that reversibly, selectively andstoichiometrically chemisorb dioxygen in a process involving the twoelectron oxidation of dimetallic sites with concurrent reduction of twoequivalents of sorbed O₂ to form μ-η¹,η²-peroxide ligands. Thecoordinating ability of counteranions, ClO₄ ⁻, PF₆ ⁻, BF₄ ⁻, CF₃SO₃ ⁻and NO₃ ⁻ determine the O₂ affinity of the deoxygenated forms. Thesecrystals undergo reversible single-crystal-to-single-crystaltransformations on the stoichiometric uptake of O₂. During this processO₂ replaces the two counterion ligands. Thus the Co ions are sixcoordinated in both the oxy and deoxy states. Rapidhydration/dehydration processes involving several molecules ofco-crystallized water per unit cell accompany the reaction. Thefollowing cationic oxy complexes can be synthesized by mixing thedinucleating pro-ligand, bpbpH, the appropriate carboxylic acid and basein stoichiometric amounts in mixtures of methanol, acetone and H₂O underaerobic conditions: [(bpbp)Co₂(O₂)(O₂CR)](A)₂ where R is methyl, phenyl,CH₂Cl, CHCl₂, CCl₃, or CH₂CH₂S⁻ and [{(bpbp)Co₂(O₂)}₂(bdcR₄)](A)₄ whereR is

and A is a ClO₄ ⁻, PF₆ ⁻, BF₄ ⁻, CF₃SO₃ ⁻, or NO₃ ⁻ counterion. Thisreaction results in dark solutions from which the near black Co(III) oxyforms crystallize over hours to days. Rapid precipitation forms lightbrown amorphous powders, which are inactive or only minimally activetowards reversible O₂ binding. On heating, the crystalline materialschange to a pink color due to the loss of O₂ and the generation of“deoxy” materials containing the counterpart Co(II)O⁴⁻ containingmaterials. On cooling back to room temperature the dark color re-emergesas the materials chemisorb O₂ from the air to form the Co(III)₄ oxymaterials. The synthesis of [{Co₂(bpbp)(O₂)}₂(bdc)](BF₄)₄.5H₂O.MeOH isas follows: a solution of sodium 1,4-benzenedicarboxylate (Na₂bdc; 55.0mg, 0.26 mmol) is dissolved in H₂O (10 mL) and added dropwise to asolution of Co(BF₄)₂.6H₂O (356.7 mg, 1.05 mmol) and bpbpH (299.8 mg,0.52 mmol) in acetone-MeOH (1:1, 50 mL). Slow evaporation of theresulting dark brown solution yields black needle-like crystals whichare collected by filtration, washed with ice cold H₂O (3×5 mL) andair-dried (289.7 mg, 0.15 mmol, 57.0%).[{Co₂(bpbp)(O₂)}₂(bdc)](NO₃)₄.15H₂O is prepared as above but usingCo(NO₃)₂.6H₂O, yielding black needle-like crystals (370.2 mg, 0.20 mmol,76.7%). [{Co₂(bpbp)(O₂)}₂(bdc)](OTf)₄.5H₂O is prepared as above but fromCo(OTf)₂, yielding black needle-like crystals (273.1 mg, 0.12 mmol,47.7%). Synthesis of [{Co₂(bpbp)(O₂)}₂(NH₂bdc)](NO₃)₄.11H₂O is asfollows: 2-Aminoterephthalic acid (102.0 mg, 0.56 mmol) is added to asolution of NaOH (45.0 mg, 1.13 mmol, 2 eq.) in H₂O (25 mL) and themixture is gently heated until a clear solution forms whereupon it isadded dropwise to a mixture of Co(NO₃)₂.6H₂O (655.5 mg, 2.25 mmol) andbpbpH (645.0 mg, 1.13 mmol) in acetone-MeOH (2:1, 75 mL). Slowevaporation of the resulting dark brown solution yields blackneedle-like crystals which are collected by filtration, washed with icecold H₂O (3×5 mL) and air-dried (979.3 mg, 0.52 mmol, 93.5%). Synthesisof [{Co₂(bpbp)(O₂)}₂(Cl₂bdc)](NO₃)₄.12H₂O is as follows:2,5-Dichloroterephtalic acid (112.8 mg, 0.48 mmol) is added to asolution of NaOH (38.4 mg, 0.96 mmol, 2 eq.) in H₂O (10 mL) and themixture is gently heated until a clear solution forms whereupon it isadded dropwise to a mixture of Co(NO₃)₂.6H₂O (558.8 mg, 1.92 mmol) andbpbpH (549.4 mg, 0.96 mmol) in acetone-MeOH (3:1, 100 mL). Slowevaporation of the resulting dark brown solution yields blackneedle-like crystals which are collected by filtration, washed with icecold H₂O (3×5 mL) and air-dried (575.2 mg, 0.30 mmol, 62.0%). Synthesisof [{Co₂(bpbp)(O₂)}₂(F₄bdc)](NO₃)₄.18H₂O is as follows:tetrafluoroterephtalic acid (114.3 mg, 0.48 mmol) is added to a solutionof NaOH (38.4 mg, 0.96 mmol, 2 eq.) in H₂O (15 mL) and the mixture isgently heated until a clear solution forms whereupon it is addeddropwise to a mixture of Co(NO₃)₂.6H₂O (558.8 mg, 1.92 mmol) and bpbpH(549.8 mg, 0.96 mmol) in acetone-H2O (1:1, 50 mL) whereupon aprecipitate forms. Acetone is added until a clear solution forms(approximately 50 mL) and the reaction mixture is stirred at roomtemperature for approximately 7 days whereupon it turns into a slightlygelatinous appearance. Filtration through celite yields a clear darkbrown solution which upon slow evaporation gives black needle-likecrystals which are collected by filtration, washed with H₂O (3×5 mL) andair-dried (622.3 mg, 0.32 mmol, 67.3%). Example water accommodatingtransition metal oxides include composite materials, such as nickelcobaltite. Optionally, a resistive heating element is provided inthermal communication with the oxygen absorbing solid-state material todrive release of stored oxygen. Optionally, the oxygen absorbingsolid-state material absorbs oxygen when a pressure of oxygen isincreased. Optionally, the oxygen absorbing solid-state materialreleases oxygen when a pressure of oxygen is decreased. Example halfreactions and overall reactions for charging and discharging areprovided in FIG. 4 .

TABLE 1 Overview of redox chemistry during charging. Anode Half ReactionCathode Half Reaction Stage 1 Charging M1OX + e⁻ → M1O_(X−1) + O⁻M2O_(Y) + O⁻ → M2O_(Y+1) + e⁻ Overall Reaction: M1O_(X) + M2O_(Y) →M1O_(X−1) + M2O_(Y+1) Stage 2 Charging M1O_(X−1) + e⁻ → M1O_(X−2) + O⁻M2O_(Y+1) + O⁻ → M2O_(Y+2) + e⁻ Overall Reaction: M1O_(X−1) + M1O_(Y+1)→ M2O_(X−2) + M2O_(Y+2) . . . Stage N Charging M1O_(X−(N−1)) + e⁻ →M1O_(X−N) + O⁻ M2O_(Y+(N−1)) + O⁻ → M2O_(Y+N) + e⁻ Overall Reaction:M1O_(X−(N−1)) + M2O_(Y+(N−1)) → M1O_(X−N) + M2O_(Y+N)

TABLE 2 Overview of redox chemistry during discharging. Anode HalfReaction Cathode Half Reaction Stage 1 Discharging M1O_(X) + O⁻ →M1O_(X+1) + e⁻ M2O_(Y) + e⁻ → M2O_(Y−1) + O⁻ Overall Reaction: M1O_(X) +M2O_(Y) → M1O_(X+1) + M2O_(Y−1) Stage 2 Discharging M1O_(X+1) + O⁻ →M1O_(X+2) + e⁻ M2O_(Y−1) + e⁻ → M2O_(Y−2) + O⁻ Overall Reaction:M1O_(X+1) + M2O_(Y−1) → M1O_(X+2) + M2O_(Y−2) . . . Stage N DischargingM1O_(X+(N−1)) + O⁻ → M1O_(X+N) + e⁻ M2O_(Y−(N−1)) + e⁻ → M2O_(Y−N) + O⁻Overall Reaction: M1O_(X+(N−1)) + M2O_(Y−(N−1)) → M1O_(X+N) + M2O_(Y−N)

Although not depicted in the figures, an energy storage device mayoptionally comprise further comprise a first current collector inelectrical contact with the first electrode and a second currentcollector in electrical contact with the second electrode. Optionally,the first current collector and the second current collector eachindependently comprise a compliant porous carbon material, which may beuseful for accommodate expansion and contraction of materials of thesolid-state energy storage device, such as the electrodes, theelectrolyte, and other materials of the solid-state energy storagedevice.

Optionally, a solid-state energy storage device is fabricated by meansof atomic layer deposition, a form of chemical vapor depositioninvolving precursor chemicals and a two stage deposition process, suchas where the deposition chamber must be purged between processingstages. Atomic layer deposition (ALD) permits the formation of layershaving a thickness of several nanometers or less and intricate surfacefeatures of similar dimensions. Advanced magnetron sputtering may alsocorrespond to a useful deposition technique. Multiple depositionchambers may be useful for performing sequential deposition operations.

It will be appreciated that the above reference to ALD does not precludethe use of other nanofabrication techniques applicable tomicro-circuitry either extant or in development, including CVD, thermalevaporation, epitaxial techniques, ultraviolet or X-ray lithography,holographic lithography, thermal evaporation, laser ablation ordeposition.

In exemplary embodiments, individual “sandwiches” or cells compriseelectrolytic layers alternating with metal containing electrodes. Actualcharge storage occurs within the electrodes, such as by a process inwhich ions are oxidized/reduced on or within the electrodes.

The benefits of the ALD and advanced magnetron sputtering fabricationtechnique useful with embodiments described herein are several. Forexample, they permit a high degree of consistency and repeatability andthus a low defect rate. In addition, because they support the formationof three-dimensional, high radius features at very small scales, thesetechniques permit the designer to increase interfacial surface area bymany multiples over that afforded by featureless flat surfaces withinthe same volume. For example, surfaces having contoured topologies thatprovide increased surface area are useful with various embodiments.Certain fabrication techniques, if properly controlled, may also allowfor precise control over the crystal structure of materials and mayallow formation of single crystal, polycrystal, or amorphous materials.

In addition, energy storage devices of various embodiments may be builtup incrementally, layer by layer. Capacity within a given footprint maybe optionally controlled by varying the number of layers and thedimension of depth. The disclosed solid-state energy storage devicesfurther lend themselves to the construction of power distributionnetworks where the energy storage devices are made modular and modulesare interspersed with active circuitry or transducers. It will beappreciated that strategic depositions performed according to the ALDprocess or advanced magnetron sputtering can support such architectures.Optionally, the number of modules within such overall architectures maybe arbitrarily small or large in number, such as 2 or 3 or as many asabout 10 or more than about 10. Modules residing within sucharchitectures may collectively assume the form of star and hub networks,redundant rings, or meshes, for example.

It will be appreciated that, in embodiments, the term “gel” refers to anon-fluid colloidal network or polymer network that is expandedthroughout its whole volume by a fluid. As used herein, gels areexpressly excluded from consideration as solid materials. Exampleelectrolytes that comprise a gel include, but are not limited to,Nafion, LiPON, etc., which may be used, for example, in thin filmlithium batteries. In some embodiments, electrolytes that comprise a gelcannot be prepared by high temperature deposition methods. It will beappreciated that solid-state electrolytes that comprise a gel cannot beprepared by atomic layer deposition. In addition, electrolytes thatcomprise a gel cannot withstand exposure to temperatures exceeding, forexample 100° C., 200° C., 300° C., etc., without undergoing substantialdamage to the electrolyte structure and/or without resulting in asubstantial decrease in the ionic conductivity of the electrolytestructure.

FIG. 5A provides an overview of a process for making an energy storagedevice, in accordance with some embodiments. Initially, a substrate 505is subjected to a deposition process 508, such as an atomic layerdeposition process, where material of a first electrode 510 is depositedonto substrate 505. Use of atomic layer deposition processes isadvantageous for controlling the thickness of first electrode 510.Substrate 505 may correspond to any suitable substrate. As an example,substrate 505 may correspond to a portion of an integrated circuit, forexample. Substrate 505 may alternatively correspond to a topmost layerof another energy storage device.

Next, first electrode 510 is subjected to a second deposition process513, in order to form a solid electrolyte 520 over the first electrode510. For example, second deposition process 513 may correspond to anatomic layer deposition process to form a ceramic solid electrolyte. Useof atomic layer deposition processes is advantageous for controlling thethickness of solid electrolyte 520, as is advanced commercialsputtering.

Next, solid electrolyte 520 is subjected to a third deposition process523, such as an atomic layer deposition process, where material of asecond electrode 530 is deposited onto the solid electrolyte 520. Use ofatomic layer deposition processes is advantageous for controlling thethickness of second electrode 530, as is advanced commercial sputtering.

Certain properties of the energy storage systems and devices describedherein are strongly interrelated. For example, the highest level ofperformance may be achieved through system synergies in which thephysical disposition of the active materials supports the most completeoxidation/reduction reactions. As noted above, in some embodiments,higher performance may correspond to using electrodes that areparticularly thin or that exhibit high surface area. In someembodiments, higher performance may be achieved by using both sides ofone or more electrodes in an energy storage device, which may beobtained using a stacked geometry in which a first surface of anelectrode is positioned proximal to a first solid electrolyte and asecond surface of the electrode is positioned proximal to a second solidelectrolyte.

In some embodiments, an energy storage device may thus comprise severalor hundreds of cells, or more, stacked together in a multi-layerarrangement. In some embodiments, a multi-layer arrangement may comprisea series of stacked energy storage cells in which the anode of one cellserves as the cathode of the cell stacked adjacent to it. In someembodiments, a multi-layer arrangement may comprise a plurality ofstacked energy storage cells in which the anode of one cell also servesas the anode of an adjacent cell and/or in which the cathode of one cellalso serves as the cathode of an adjacent cell.

FIG. 5B provides an overview of a process for making a stacked energystorage device, in accordance with some embodiments, and continues theprocess depicted in FIG. 5A. Second electrode 530 is subjected to afourth deposition process 533, in order to form a second solidelectrolyte 540 over the second electrode 530. For example, fourthdeposition process 533 may correspond to an atomic layer depositionprocess to form a ceramic solid electrolyte. Use of atomic layerdeposition processes is advantageous for controlling the thickness ofsecond solid electrolyte 540.

Next, second solid electrolyte 540 is subjected to a fifth depositionprocess 543, such as an atomic layer deposition process, where materialof a third electrode 550 is deposited onto second solid electrolyte 540.Use of atomic layer deposition processes is advantageous for controllingthe thickness of third electrode 550.

It will be appreciated that additional electrolyte/electrode bilayersmay be deposited over an uppermost electrode, similar to the processingdepicted in FIG. 5B, in order to form stacked energy storage devices ofany desired thickness and number of layers.

In some embodiments, a solid electrolyte may exhibit a crystallinestructure. The solid electrolyte may exhibit a variety of crystal forms,including single crystal and polycrystal. In embodiments where the solidelectrolyte includes crystalline material, the solid electrolyte maytake on different crystal forms, depending on the specific materialconfiguration of the solid electrolyte. FIG. 6 provides a schematicillustration of a first example crystal structure 600 of a solidelectrolyte. It will be appreciated that the crystal structure 600illustrated may correspond to a ceria or zirconium crystal structure,which is provided here as an example only, and that other crystalstructures are possible. For example, in embodiments, the solidelectrolyte may comprise a perovskite ceramic, a ceramic having aperovskite structure, a zirconium ceramic, a ceria-gadolinia ceramic, analumina ceramic, any variant of these, including any doped variant, andany combination of these.

In FIG. 6 , various chemical elements make up the crystal structure 600.For example, first atoms 605, such as metal atoms, may comprise aportion of the crystal structure 600, and second atoms 610, such asoxygen atoms, may comprise a portion of the crystal structure 600.Various defects may be included in the crystal structure 600, which maybe naturally occurring or intentionally introduced. As illustrated,crystal structure 600 includes voids or crystallographic defects 615,which may correspond to vacancy defects, for example, where atoms of thecrystal structure are missing. Voids and crystallographic defects 615may be useful for allowing transmission of oxygen anions through thecrystal structure 600, and provide for the ability of oxygen anions toefficiently migrate through the solid electrolyte. It will beappreciated that other crystal structure features beyond voids orcrystallographic defects such as vacancy defects may also exist in thesolid electrolyte, such as crystallographic defects includinginterstitial defects, line defects, planar defects, bulk defects, andlattice imperfections. An interstitial defect 620 is illustrated. Eachof the voids or crystallographic defects may, in some embodiments,contribute to the ability of ions to efficiently migrate through a solidelectrolyte.

FIG. 7 provides a schematic illustration of another crystal structure700, which includes a first metal 705, oxygen atoms 710, andcrystallographic defects 715. Here, crystallographic defects 715 maycorrespond to vacancy defects. The crystallographic defects 715 may begenerated, for example, by introduction of one or more dopants 720 intothe crystal structure 700. In some embodiments, the dopants 720 andcrystallographic defects 715 may be introduced, for example, during theformation of the crystal structure, such as during an atomic layerdeposition process. In some embodiments, the dopants 720 andcrystallographic defects 715 may be introduced after the crystalstructure 700 is formed, such as by an ion implantation or dopingprocess. Useful dopants include, but are not limited to, alkali metaldopants, alkaline earth dopants, group 3 dopants, lanthanide dopants,titanium oxide dopants, hydrogen dopants, silver dopants, and/or leaddopants.

In embodiments, when an oxygen anion is added to the crystal structure700 at a crystallographic defect 715, the electronic configuration ofthe crystal structure may change, such as due to the extra electronscarried by the oxygen anion. This configuration may create an unstablestructure, and so the oxygen atoms may rearrange to accommodate theextra material added to the crystal structure and in this way allowoxygen anions to migrate through the crystal structure.

In other embodiments, the solid electrolyte does not comprise acrystalline material. For example, the solid electrolyte may comprise anamorphous material. Without wishing to be bound by any theory, somesolid electrolytes may exhibit different electrical conductivities incrystalline and amorphous forms. In a crystalline or polycrystallineform, for example, some solid electrolytes behave as electricalconductors, which diminishes their utility in some devices describedherein. For example, using electrolytes having a relatively highelectrical conductivity may result in a self-discharge of any storedenergy at a rate beyond which charge may be stored for an appreciableamount of time. In some cases, the self-discharge rate may be so largeas to simply correspond to a short circuit between the electrodes. Forsome embodiments, use of an electrolyte having an amorphous structure isadvantageous, as such an amorphous structure may exhibit a very lowelectrical conductivity, minimizing the self-discharge rate and allowingstorage of large amounts of charge for long periods of time.

It will be appreciated that, in some embodiments, the energy storagedevices described herein may comprise extremely small devices, as theelectrodes and electrolyte may comprise layers having thicknesses assmall as about 1 nm. For example, total thicknesses of a unit cell maybe as small as about 3 nm, for example, or as large as about 1 μm. Someunit cell embodiments may comprise larger thicknesses, however, andmulti-cell devices may take on any suitable thickness, as the number ofunit cells is virtually without limit. These small unit cell dimensionsmay provide for a number of the advantageous properties of the devices.For example, in embodiments, the devices may exhibit extremely largeelectrical energy densities when charged, such as greater than or about10 J/cm³, greater than or about 50 J/cm³, greater than or about 200J/cm³, greater than or about 500 J/cm³, greater than or about 1000J/cm³, greater than or about 5000 J/cm³, greater than or about 10000J/cm³, greater than or about 50000 J/cm³, or selected from 10 J/cm³ to50000 J/cm³. Although the amount of energy stored by a single cell maybe small, the dimensionality of the cells may allow many hundreds orthousands or more cells to be included within a small volume, magnifyingthe overall energy storage capacity greatly.

Lateral dimensions for the devices may also take on any suitable value,and may (at least) linearly contribute to the amount of energy stored bythe devices. For example, in some embodiments, the lateral dimensions ofthe electrodes and the solid electrolyte may be as small as or about 20nm or less, and may be limited by the deposition abilities used duringfabrication. Various masking and lithographic processes may be used, forexample, to achieve lateral dimensions as small as or about 10 nm. Inother embodiments, the lateral dimensions may take on larger values,such as greater than or about 1 μm, greater than or about 10 μm, greaterthan or about 100 μm, greater than or about 1 mm, greater than or about1 cm, or greater than or about 10 cm. Again, the maximum lateraldimensions achievable may be limited by the deposition abilities used,but are virtually without limit.

One advantage of such miniaturized energy storage devices is thatmultiple individual devices may be attached to one another to form anenergy distribution network. Energy distribution networks of this naturemay be useful for providing power at the point of load, minimizing powertransmission distances and associated resistive losses and heatgeneration. Energy distribution networks may also be useful forsequestering attached devices from fluctuating electrical loadsengendered by other components. For example, when included in anintegrated circuit, such as in combination with inductive coupling, anenergy distribution network may protect circuits from electricalfluctuations generated by circuit blocks elsewhere on the wafer.

Another advantage is that backup power may be provided in the event ofthe failure of any one of the storage devices in the distributionnetwork, and a portfolio of energy resources may be provided within theconfines of a single system on a chip, for example. Networking of thedevices in an energy distribution may optionally be achieved using oneor more addressable switching transistors, which can be used to isolateindividual blocks or energy storage cells/stacks and/or to routecurrent/voltage to components that have had a failure of their primarypower source.

Optionally, the individual cells may in an energy distribution networkbe connected in series or in parallel and any combinations of series andparallel connections may be made. Such connections may be made highlyconfigurable by the inclusion of switching transistors to set up anddismantle temporary circuit paths.

FIG. 8 provides a schematic overview of a system 800 including a varietyof energy storage devices 805, 810, 815. System 800 may correspond to asingle integrated circuit configured as a system-on-chip, or maycorrespond to individual or integrated components, in any configuration.The energy storage devices 805, 810, 815 may be used individually asenergy sources for one or more other components of system 800, but mayalso be used in an energy distribution network, as described above, toprovide power to any one or more components. In such a configuration, atransistor network may be included, for example, to allow forindividually switching the flow of electrical current from anyindividual energy storage device 805, 810, 815 to any individualcomponent.

As illustrated, however, energy storage devices 805, 810, 815 are shownas separate energy storage devices, providing power to only one or asubset of components of system 800. For example, energy storage device805 is illustrated as providing power to a central processing unitcomprising four individual processing cores. Energy storage device 810is illustrated as providing power to a memory unit, a network unit, andan input/output unit. Energy storage device 815 is illustrated asproviding power to the input/output and a graphics processor. It will beappreciated that the electrical connection providing power from theenergy storage devices to another component may be switchably achieved,such as by using one or more transistors, relays, or other controllableswitching circuits.

FIG. 9A provides a schematic illustration of a section of a multilayerenergy storage device 900. Here, alternating electrodes 905 and 910 areconnected in a parallel configuration, such that the device comprises asingle parallelized energy storage device. For example, every otherelectrode is electrically connected on a first end, while the remainingelectrodes are electrically connected on the opposite end. Otherconfigurations are possible, including series configuration, combinedseries and parallel configuration, and electrical connections to theelectrodes may be made at any suitable position. As illustrated, a firstset of electrodes exhibit a first potential (V₁), while a second set ofthe electrodes, interspersed between the first set of electrodes,exhibit a second potential (V₂), such that a potential differencebetween the electrodes is V₁−V₂. Solid electrolytes 915 are positionedbetween each adjacent electrode in FIG. 9A.

FIGS. 9B and 9C provides a schematic illustrations of sections of energystorage devices 950 and 980. Here, electrodes 955, 960, 985, and 990 andelectrolytes 965 and 995 are provided in interdigitated configurations,such that the devices exhibit large surface area. Such a configurationmay provide an effective multilayer-type structure. It will beappreciated that combinations of structures corresponding to FIG. 9A andFIG. 9B may be used, such as illustrated in FIG. 9C, where an energystorage device comprises stacks of interdigitated electrode elements,separated by an electrolyte. When provided in such a stackedconfiguration, interdigitated electrode elements may be interdigitatedon both sides (similar to shown in FIG. 9B), or interdigitated on oneside. When provided in stacked interdigitated configurations,interdigitations extending opposite directions on an electrode may belined up (top stack configuration in FIG. 9C), or displaced from oneanother (bottom stack configuration in FIG. 9C), or combinations may beused.

In addition to stacked energy storage devices and interdigitatedelectrodes, other techniques may be useful for increasing the surfacearea of an energy storage device. For example, FIG. 10A and FIG. 10Bprovide cross-sectional schematic illustrations of a portion of energystorage devices 1000 and 1050. In energy storage device 1000, aninterface between an electrode 1005 and a solid electrolyte 1010 isshown; in energy storage device 1050, an interface between an electrode1055 and a solid electrolyte 1060 is shown. Here, the interface betweenthe electrode and the solid electrolyte is not simply a single abruptchange of one material to the other, but instead represents a transitionbetween the electrode and the solid electrolyte materials.

In FIG. 10A, the transition may be achieved by multiple separate solidelectrolyte interlayers 1015 over a larger structure corresponding tosolid electrolyte 1010 (if fabricated from bottom-up as shown) or over alarger structure corresponding to electrode 1005 (if fabricated fromtop-down as shown). As illustrated, energy storage device 1000 includessix (6) interlayers 1015, but it will be appreciated that more or fewerinterlayers may be used, such as from 1 to 30, or more. Each interlayer1015 may include electrode components 1020, which may occupy at least aportion of the interlayer 1015. Optionally, some interlayers 1015 maynot include an electrode component 1020, but may simply comprise orcorrespond to a layer of solid electrolyte material. While the electrodecomponents 1020 may be physically separated from electrode 1005, thesmall size dimensions of the interlayers 1015 and close proximitybetween interlayers 1015 and electrode 1005 may result in sufficientelectrical conductivity between electrode components 1020 and electrode1005 such that the electrode components 1020 function as if they areelectrically connected to electrode 1005. For example, each interlayer1015 may independently have a thickness of from 0.5 nm to 5 nm, such asabout 0.5 nm, about 1 nm, about 1.5 nm, about 2 nm, about 2.5 nm, about3 nm, about 3.5 nm, about 4 nm, about 4.5 nm, or about 5 nm. Similarly,each electrode component 1020 may independently have a cross-sectionaldimension (e.g. a thickness and/or a lateral dimension) of from 0.5 nmto 5 nm, such as about 0.5 nm, about 1 nm, about 1.5 nm, about 2 nm,about 2.5 nm, about 3 nm, about 3.5 nm, about 4 nm, about 4.5 nm, orabout 5 nm. Such interlayers comprising both solid electrolyte materialand electrode material may be fabricated by a co-deposition orsimultaneous deposition of both the solid electrolyte material andelectrode material and/or suitable precursors or components thereof.

In FIG. 10B, the transition may be achieved by multiple separatealternating depositions of solid electrolyte interlayers 1065 andelectrode interlayers 1070 over a larger structure corresponding tosolid electrolyte 1060 (if fabricated from bottom-up as shown) or over alarger structure corresponding to electrode 1055 (if fabricated fromtop-down as shown). As illustrated, energy storage device 1050 includesthree (3) solid electrolyte interlayers 1065 and three (3) electrodeinterlayers 1070, but it will be appreciated that more or fewerinterlayers may be used, such as from 1 to 30, or more. While theelectrode interlayers 1070 may be physically separated from electrode1055, the small size dimensions of the solid electrolyte interlayers1065 and the electrode interlayers 1070 and their close proximity toelectrode 1055 and one another may result in sufficient electricalconductivity between electrode interlayers 1070 and electrode 1055 suchthat the electrode interlayers 1070 function as if they are electricallyconnected to electrode 1055. For example, each solid electrolyteinterlayer 1065 and each electrode interlayer 1070 may independentlyhave a thickness of from 0.5 nm to 5 nm, such as about 0.5 nm, about 1nm, about 1.5 nm, about 2 nm, about 2.5 nm, about 3 nm, about 3.5 nm,about 4 nm, about 4.5 nm, or about 5 nm. Such alternating interlayers ofsolid electrolyte material and electrode material may be fabricated byalternating deposition of the solid electrolyte material and theelectrode material, and/or suitable precursors or components thereof, ata suitable deposition time/rate to allow for the small interlayerdimensions to be created.

Advantageously, by depositing interlayers 1015 including electrodecomponents 1020 or alternating interlayers 1065 and 1070, a surface areaof the electrode active material may be increased beyond just thesurface area of the electrode 1005 to also include the surface area ofelectrode components 1020 or interlayers 1070. In some cases, theelectrode material that may participate in redox reactions maycorrespond to a surface layer and or sub-layer (such as within 0-3 nm ofthe surface), and so such a configuration may be particularlyadvantageous for some energy storage devices as a means for increasingan active surface area useful for participating in redox reactions.

As another example of a high-surface area electrode, nanoneedlestructures or nanoneedle-assembled microflowers, such as comprisingNiCo₂O₄ or MnCo₂O_(4.5) materials, may be used. The mesoporousnanoneedle structures may be used directly as an electrode or may serveas a scaffold or geometric substrate for a conformal coating of anothertransition metal or transition metal oxide, which may be or correspondto an active material of the electrode, while the nanoneedle structuremay serve, for example, as a current collector, due to its highelectrical conductivity. Such a nanoneedle-based structure may alsoprovide other advantages in addition to high surface area. Since anenergy storage device comprising the nanoneedle-based electrode also mayinclude a solid electrolyte, the physical geometry of thenanoneedle-based electrode may provide a large and interdigitatedcontact area between the electrode and the solid electrolyte, providingstrong adhesion between the electrode and the solid electrolyte,limiting delamination of the solid electrolyte from the electrode. Avariety of techniques for generating nanoneedle structures are known.For example, Lee et al. Nanoscale Research Letters (2016) 11:45, herebyincorporated by reference, describes use of NiCo₂O₄ nanoneedle arrays aselectrodes in sodium ion batteries. To generate a full energy storagedevice, a layer of solid electrolyte may be deposited over thenanoneedle-based electrode followed by subsequent generation of anadditional electrode. As noted above, a layer of a transition metal ortransition metal oxide (e.g., of thickness 1-50 nm) may be depositedover a nanoneedle structure to generate a nanoneedle-based electrode ofthe transition metal or transition metal oxide as the active material.

FIG. 11 provides a cross-sectional schematic illustration of anintegrated circuit 1100 including energy storage devices 1105 and 1110,positioned over a substrate 1115. Each of the energy storage devices1105 and 1110 are illustrated as including multiple stacked unit cells,and interdigitated configurations may alternatively or additionally beimplemented. A transistor 1120 is included in the circuit 1100,including source, drain, and gate elements. Variousinsulating/dielectric layers 1125 are included, as well as conductivetraces 1130 between various layers and device components. It will beappreciated that the energy storage devices may be distributed and/ornetworked throughout the integrated circuit as described above.

Inclusion of one or more energy storage devices in an integratedcircuit, as illustrated in FIG. 11 , may be achieved, in embodiments,because the component materials and characteristics may be compatiblewith the semiconductor fabrication processes used to manufacture theintegrated circuit. Further, the techniques used to make the energystorage devices, such as atomic layer deposition, magnetron sputtering,masking, lithography, etc., may be already utilized in the fabricationof the semiconductor devices, so additional processing systems andtechniques may not have to be developed.

FIG. 12A and FIG. 12B provide cross-sectional schematic illustrations ofa photovoltaic cell 1200 integrated with a stacked configuration energystorage device 1230. Interdigitated configuration energy storage devicesmay alternatively or additionally be implemented. Photovoltaic cell 1200may optionally comprise any suitable photovoltaic material that iscompatible with energy storage device 1230 and the fabrication processesfor making energy storage device 1230. For example, in the embodimentsillustrated in FIGS. 12A and 12B, photovoltaic cell 1200 comprises abottom electrode 1205, a p-type silicon layer 1210, an n-type siliconlayer 1215 and a top electrode 1220. Energy storage device 1230comprises multiple layers of electrodes and electrolytes, for examplesimilar to multilayer energy storage device 900 described above. A firstset of electrodes of energy storage device 1230 is illustrated as inelectrical communication with top electrode 1220 and a second set ofelectrodes of energy storage device 1230 is illustrated as in electricalcommunication with bottom electrode 1205. A load 1225 is alsoillustrated as electrically connected between bottom electrode 1205 andtop electrode 1220.

In FIG. 12A, the energy storage device 1230 is positioned directly belowand optionally in contact with bottom electrode 1205. Such aconfiguration may be desirable for example, to allow the first electrodeof energy storage device 1230 to be deposited directly on bottomelectrode 1205 during the manufacturing process. Other examples arepossible, such as where an interleaving material, such as an insulator,semiconductor, or other conducting material is positioned between bottomelectrode 1205 and energy storage device 1230. Additionally, differentphysical arrangements of the photovoltaic cell 1200 and energy storagedevice 1230 are contemplated. As an example, in FIG. 12B, thephotovoltaic cell 1200 and energy storage device 1120 are positionedside-by-side. Such a configuration may be desirable to allow energystorage device 1230 to be positioned within the spaces between adjacentphotovoltaic cells, for example. Further arrangements are contemplated,including where the energy storage device 1230 and photovoltaic cell1200 are independent components and where the energy storage device 1230is used as a standalone energy storage backup module.

It will be appreciated that providing energy storage devices inelectrical communication with photovoltaic cells may be useful, inembodiments, for modulating the output of the photovoltaic cell andminimizing variability in cell output. Additionally, when exposed tolight, the excess electrical energy generated by the photovoltaic cellmay be used to charge the energy storage device to store the excessenergy. The stored energy may then be provided by the energy storagedevice as voltage output during non-peak times, such as during the nightor on cloudy days, for example. Including the energy storage devicesdirectly on the same structure as the photovoltaic cell is furtheradvantageous for simplifying construction, integration, shipping, etc.Additionally, the use of the energy storage devices described herein maybe beneficial, for example, as the energy storage devices may have largepower densities and can receive and provide large current densities asneeded, without damaging the energy storage devices or degrading theirstorage capacities. Further, the energy storage devices may exhibitlarge cycle lives without resulting in component degradation or capacityloss, making them beneficial for use in these photovoltaic applicationsas well as other energy storage applications.

The present invention may be further understood by reference to thefollowing non-limiting examples.

A. Architecture

Like batteries, the solid-state energy storage devices and systemsdescribed herein make use of conduction of ions through an electrolyte.For example, the disclosed energy storage devices and make use ofreversible redox reactions that take place at the electrodes with ionsthat pass through the electrolyte. In the disclosed energy storagedevices, these reversible redox reactions can occur without limit, andpermit full discharge without damage. In some embodiments, an energystorage device comprises a simple construction, where two electrodes areseparated by a solid-state electrolyte.

B. Temperature

Unlike battery chemistries such as lead/acid and lithium-ion, energystorage devices described herein are not restricted by temperature andremain capable of operating within a wide range of temperatures, suchas, for example between about −100° C. and about 700° C., although someembodiments may exhibit a certain amount of temperature sensitivity. Itwill be appreciated that the energy storage devices of some embodimentscan withstand this temperature range due to the use of ceramicelectrolytes instead of liquid, gel, or polymer electrolytes. It will beappreciated that the ceramic materials used as electrolytes herein arenot commonly seen to represent electrolytes at ambient temperatures whenin bulk, but rather as dielectrics through which neither electrons norpositive ions can move.

C. Electrolyte Materials & Scale

In some embodiments, the disclosed energy storage devices use speciallydoped and extremely thin ceramic films, where the ceramic presents astructure with vacancies through which ions can flow to interface withthe electrodes. The length scales used to achieve the conductivity ofions vary somewhat from material to material. In some embodiments, thethickness of the ceramic solid-state electrolyte is between about 30 nmand about 100 nm. If the electrolyte exceeds its limits, it reverts to adielectric rather than an electrolyte, and thus will not function forenergy storage, and so in no case does the thickness equal or exceed 1μm. Conversely, if the electrolyte is too thin, opportunities exist forcatastrophic failure by shorting out, such as due to surface roughage orelectrostatic discharge from one electrode to the other through theelectrolyte. Further, if the material of the electrolyte is or isrendered electrically conductive, the electrolyte may not beparticularly useful in an energy storage device, as it may allowexcessive self-discharge.

D. Doping

Basic ceramic materials such as alumina and zirconium in pure form maypresent monolithic and nonconductive surfaces to the electrodes if usedin an energy storage device. In order to present a structure thatcontains the vacancies useful for ionic conductivity, some pure ceramicmaterials may require doping. The doping may, for example, createstructural imperfections, defects, or ion carrier sites that theextremely small thickness scale can exploit. In some cases, this amountsto creating an alloy, such as where the dopant is as much as 50% of thematerial. Na⁺ doped alumina (β-alumina), is an example.

E. Energy Density & Charge

Due to the small amounts of material incorporated into the energystorage devices at the scales used in various embodiments, only smallamounts of charge will be stored, even with a relatively high energydensity. In certain embodiments, however, such as integrated intoelectronic circuitry in semiconductor chip fabrication, this smallamount of charge can provide power at the point of load on aninstantaneous basis. In addition, inductive coupling from a nearbysource can be used in some embodiments to continuously recharge theenergy storage devices.

In more general applications, such as replacement batteries for aconsumer electronic device, such as a smart phone or laptop battery,embodiments may require multiple layers or cells to provide the neededcurrent. For example, multiple layers of energy storage devices may beconstructed on top of one another to achieve larger amounts of chargestorage. Given the small thicknesses, many thousands of layers ofelectrodes and solid-state electrolytes can, in embodiments, beconstructed within common battery pack sizes, such as on the order ofabout 1 cm to about 10 cm. Techniques, such as advanced commercialmagnetron sputtering, atomic layer deposition, and other nanoscaledeposition techniques allow economical fabrication of such multi-celleddevices.

In a specific embodiment, a combination of two electrodes and oneelectrolyte layer constitutes a single cell. Optionally, the energystorage device may include a single cell or less than about 50 cells,such as in a continuous stacking configuration. The energy storagedevice may optionally be reduced to a depth that is commensurate withcomplete integration into a wafer based microcircuit where the energystorage device shares the same wafer as the active circuitry.

F. Field Specifics

In some embodiments, multi-celled energy storage devices comprisingmultiple layers of electrodes in between electrolytes may deliver evenmore energy storage/unit size than lithium-ion can attain. Inembodiments, replacement devices can use drop-in replacement formfactors, where the energy storage device may measure a few microns to afew mm in thickness or larger, with the remaining form consistingessentially of a case enabling direct replacement in existing devices.Using inductive charging, some embodiments may store enough charge thatelectronic devices would never need direct, wired charging beyond thefirst time.

G. Chip Integration

As described in more detail below, many batteries identified as“solid-state” batteries are not truly solid-state. For example, theelectrolyte in these batteries typically comprises a gel or a powder ora colloidal suspension. It will be appreciated that these materialscannot withstand large temperature variations used in commonsemiconductor fabrication process, and thus are incompatible withintegrated circuits, for example. Gel electrolytes behave analogously toaqueous electrolytes where crystallinity is not present and ions are notbound but are free to pass across the fluid or semifluid medium,impelled by electrical forces. Other devices may have a crystallineelectrolyte, but use a liquid electrode.

In contrast, the energy storage devices described herein make use ofrigid crystalline lattice structures and amorphous structures. Forexample, defects may be deliberately and artfully introduced to acrystal lattice in order to provide transient pathways for the movementof ions. Similarly, defects or other irregularities may be present in anamorphous structure, providing ion transmission pathways. These pathwaysmay be engineered and organized by various techniques involving theintroduction of chemical dopants or by the imposition of strain or bythe application of outside forces, either transient or persisting. Suchforces tend to deform the crystal lattice or solid structure such thatpaths for ionic migration become present, for example. These designstrategies executed on the molecular and supramolecular level may beused to regulate the volume of ionic flow, and the process may involvebeneficial nonlinearities with respect to ionic volume that may beexploited.

H. Energy Storage Device Architecture

In a solid electrolyte, such as a thin ceria stabilized zirconia layersituated between two metal or metal oxide electrodes, oxygen ions mayshuttle between the electrodes bearing opposing charges. Without wishingto be bound by any theory, the inventors believe that the positive ionsmove by traversing through the interstices of a fairly rigid crystallinelattice of extremely limited depth (thin-film), but rich in oxygenvacancies, and it is the oxygen vacancies that permit the free movementof positive ions. A trade-off exists between high ionic conductivity andmultiple-layer requirements. The movement of ions through thesolid-state electrolyte may also be further tuned by the imposition ofexternal stresses, such as those caused by a bi- or multi-layerelectrolyte, that deform the lattice and widen the passageways for ionicmovement. In either stressed or unstressed cases, the ions participatingin energy storage act as replacements for atoms distributed within theelectrolyte, and these ions hop from site to site.

I. Temperature Range and Integrated Circuit Integration

The completely solid, gel-free energy storage devices disclosed hereinare capable of withstanding very large temperature variations. Forexample, some embodiments may be useful between about −100° C. and about800° C., and, more practically, at temperatures of between 0° C. and 50°C. In addition, the devices, due to the lack of liquid or gel materials,may be rugged and capable of integration into active semiconductorcircuitry. In terms of size reduction, this can reduce, for example, thesize of an integrated circuit, such as a central processing unit, byabout 70%, due to the elimination of pin connectors and attendantcircuitry, in some embodiments, which may be accompanied by acorresponding reduction of heat generation. In addition, the energystorage devices, such as when coupled inductively, permit redundantinstantaneous power at point of load.

Additionally, the energy storage device can take the form, in someembodiments, of a network of cells. Printed conductive traces may conveythe stored energy to its destination and switching matrices may allowfor powering any of the circuit components by any of the cells, in anycombination. For example, some cells may power logic circuits, whileother cells may power mixed signal circuits.

Switching between and among energy storage cells may take the form ofstar and hub architectures, redundant rings, or mesh networks with orwithout intelligence. Such architectures may serve to support power atthe point of load design strategies or islanding of defective cells oradjustments in voltage and current by making cell to cell connectionswitchable.

It will be appreciated that, because of the flexibility afforded by thematerials and architectures used in the energy storage devices, an arrayof cells may be planar, three dimensional, or may comprise a successionof stacked planes, for example. In addition, planar inductors may,optionally, be incorporated along with the storage cells such thatislands of energy storage may be inductively coupled with one another,reducing the number of conductive pathways and the mass and volume of anintegrated circuit incorporating energy storage.

In some embodiments, the materials that comprise an energy storagedevice may be rendered rigid and unyielding or flexible, depending uponthe thickness of the material and the presence or absence of porositywithin it. Energy storage may thus be incorporated in flexible thinfilms such as displays or thin film photovoltaic cells or in energyharvesting devices dependent upon the movement of membranes to generateelectrical power, for example. In addition, caseless batteries may beconstructed in which the electrodes and electrolytes provide structuralintegrity to the batteries. In some embodiments, the energy storagedevices may also be integrated with planar energy harvesting radiofrequency antennas or with generator and actuator MEMS elements, so thatmicroelectromechanical energy storage, power electronics, and signalprocessing may be incorporated into a single wafer with a high degree ofsynergy and integration among the separate elements.

J. Gel-Free

Embodiments of the present invention relate to solid-state energystorage devices and methods of making solid-state energy storage devicein which components of the devices are truly solid-state (i.e., they donot comprise a gel). The solid-state battery nomenclature is not new butit has always been misleading in the prior art. Many “solid-statebatteries” utilize either gels or in some case powders for theelectrolyte layers and never homogenous, consolidated solid materialsthat can integrate into semiconductor chips directly, for example. Gelmaterials prohibit both incorporation within VLSI/ULSI chips, andrestrict temperature ranges to approximately ambient.

Solid-state electrolyte layers have been utilized in some solid oxidefuel cells. When used in a solid oxide fuel cell, solid-stateelectrolyte layers normally conduct ions at a practical rate only atextremely elevated temperature, such as exceeding 600° C. However, thesolid electrolyte layers described herein exhibit high ionicconductivity, which may approximate or exceed that of liquid or gelelectrolytes, even at ambient or near ambient temperatures. The ambienttemperature ionic conduction exploited herein also offers furtheradvantages of preserving high electrical resistance and dielectricstrength, which are commonly sacrificed in solid-state supertonicconductors at high temperatures.

In exemplary embodiments, gaseous oxygen (O₂) and/or oxygen ions (e.g.,O⁺, O⁻, or O²⁻) are responsible for charge transport and formation ofthe electrochemical bonds (redox) by which electrical charge is storedand conserved. Other ionic species may also be useful, depending on theparticular construction and chemistry employed, such as nitrogen ions,sulfur ions, chloride ions, protons, etc. A number of transportmechanisms may invoke the passage of ions through the structure of thesolid electrolyte layer. For example, vacancies within the structure maybe an important source of ion transport.

It will be appreciated that vacancies may represent defects, and may bepresent when a ceramic has been doped with another chemical whichresults in a departure from the regularity of the local crystalstructure present in the pure ceramic. Such defects may be analogous to“holes” in P type semiconductors, for example. It may be advantageous ifthe ceramic and/or the dopant contains the element that will be ionized,and some of that element may be dislodged from the crystal structure.Additional ions may be drawn from the anode or the cathode, or from theatmospheric air if oxygen ions participate in the redox reactions.

The ionic conduction modes in ceramic electrolytes are very differentfrom those present in aqueous or polymer electrolytes where no localcrystal structure is present and where ions are released by means ofelectrolysis or simply pass through the fluid medium from theelectrodes. In true solid electrolytes, as opposed to gels, bothchemistry and mechanical forces play a role in ionic migration as doesthe phase of the local crystal structure.

The addition of dopants alone may not provide a high degree of ionicconductivity under ordinary circumstances, and some solid electrolytematerials will not conduct ions at all at macro scale thicknesses and atambient temperatures, for example. In some embodiments, violent flexuresand dislocations of the lattice structure are required to supportinterstitial movements of ions.

Such flexures may take the form of phonons, that is, thermally inducedperiodic oscillations at audio frequencies or more enduring surfacestrains imposed by the fabrication process or by the presence ofmicro-actuators such as piezoelectric elements that exert shear forces.Either mechanism may provide spaces through which positive ions may betransported.

It will be appreciated that zirconia and other ceramics may be suitableas solid electrolytes. In some embodiments, useful ceramics includedoped ceramics. For example, calcium, magnesium, dysprosium, yttrium,aluminum, cerium, ceria, ytterbium, and stabilized zirconias may also beuseful solid electrolytes.

K. Fabrication

In embodiments, a solid-state electrolyte layer, which may be aconsolidated structural layer, offers many performance advantages. Forexample, the structural integrity conferred by a solid electrolytecombined with solid electrodes may eliminate the need for an externalcase, in some embodiments. For example, in one embodiment, the energystorage device can be naked, i.e., not associated with any otherstructural materials. In some embodiments, the energy storage device maybe built up as an integral circuit element within a larger microcircuitwith wafer fabrication techniques. These examples may not possible withconventional battery technologies. The solid-state energy storagedevices described herein also may possess inherent physical robustnessand a high immunity to shock, vibration, and temperature extremes. Inaddition, the solid-state energy storage devices described herein arehighly scalable such that they may be closely coupled to such entitiesas MEMS devices and microfluidic systems.

In exemplary embodiments, a solid-state energy storage device becomes,in essence, another circuit element in an integrated circuit andfacilitates the realization of optimal circuit paths and groundingschemes because it lends itself to strategic placement within theoverall circuit. In some embodiments, this can eliminate as much as 70%of the circuitry (e.g., the portion served by power pins) in existingVLSI/ULSI chips, greatly reducing size and heat generation.

L. Point of Load Power and Inductive Charging

Solid-state construction has implications that are as potentially asrevolutionary with respect to electrical charge storage as they havebeen to active circuitry when transistors largely replaced vacuum tubes(thermionic valves) more than a half-century ago. For example, just astransistors invoke different mechanisms for controlling the passage ofcurrent through a circuit and realization of voltage and current gain,solid-state energy storage devices may utilize unique mechanisms forstoring and releasing electrical charge at the point of load. Alsoimportantly, solid-state energy storage devices exhibit an ability tocharge rapidly by inductive coupling (rapidity due to the ability toresist overcharging), permitting wireless charging and potentiallyeliminating need for nearby power sources entirely.

It should be understood that, in various embodiments, the solid-stateenergy storage devices described herein categorically reference redoxreactions. In exemplary embodiments, charge storage may be achievedthrough truly reversible redox reactions occurring some little distanceinto the depths of the electrode layer. That depth may be in theangstroms or into the low nanometers, and, to be more specific, lessthan 10 nanometers. Oxygen ions may form the basis of or otherwise takepart in the redox reactions. In this text, oxygen may stand in for anyother useful ion.

Without wishing to be bound by any theory, ions may enter and leave theelectrodes during the charge/discharge cycles, and may reach depths ofabout 0.2 nm to about 10 nm, such as about 0.5 nm, about 1 nm, about 2nm, about 3 nm, about 4 nm, about 5 nm, about 6 nm, about 7 nm, about 8nm, about 9 nm, about 10 nm, or any combination of ranges between any ofthese specific values. In exemplary embodiments, the electrodesthemselves range in overall depth/thickness from between about 7 nm toabout 50 nm.

Uniquely, multiple redox reactions may be invoked, and successivelyhigher oxidations may be formed at successively higher input voltages.For example, in some embodiments, exemplary electrode materialscomprise, consist of, or consist essentially of elemental metals orcapable of forming a sequence of oxidized forms of progressively greatermolecular weight that incorporate additional amounts of the ionicspecies. For oxygen, these may include, for example, monoxides,dioxides, trioxides, tetroxides, pentoxides, hexoxides, heptoxides, andso on. In some embodiments, hydrides, nitrides, sulfides, chlorides,etc., may be substituted for oxides. Work functions for candidatematerials may, for example, range between about 4 electron volts andabout 5 electron volts and may also include values between these limits.

In exemplary embodiments, electrolyte layers comprise ceramiccompositions supporting expeditious transfer of positive ions from theanode to the cathode or from the cathode to the anode at ambient or nearambient temperatures. Transfer rates optionally range from about 10 toabout 50 Siemens per centimeter, and these rates may be greater inarchitectures where the electrolyte thickness is less than about 58 nm.Useful ceramic compositions include a number of perovskites andperovskite-related oxides, as well as many zirconium ceramics, such aszirconia-scandia, Zr_(1-x)Sc_(x)O_(2-δ) and the cheaper zirconiumstabilized by yttria, and ceria-gadolinia, Ce_(1-x)Gd_(x)O_(2-δ) (CGO),alumina and β-alumina formulated with a number of dopants such asceramic forms of Na⁺, K⁺, Li⁺, Ag⁺, H⁺, Pb₂ ⁺, Sr₂ ⁺ or Ba₂, TiO, TiO₂,Ti₂O₃, etc.

M. Evacuated Electrolyte

Alternatively, the electrolyte layer may be largely evacuated, and theresulting cavity may be supported with minute spacers measuring betweenabout 20 nm and about 100 nm, for example. In such instances, the cavityis optionally filled with gaseous oxygen (or hydrogen or nitrogen) at apressure of about 0.1 bar, or about 0.2 bar or about 0.3 bar, or atfractional or intermediate values or ranges between these statednumbers.

In one embodiment, the gas may, for example, be ionized by a pair oflateral electrodes that impose a transient high voltage on the gas, suchas a voltage that imparts an electric field of sufficient strength toionize the gas.

N. Enhanced Ionic Conductivity Dependencies

Thin-film scale and temperatures. Invoking high ionic conductivity forpurposes of fabricating energy storage devices via thin-film depositionof the solid-state electrolytes may involve two aspects. The first,thickness of the film, may dominate at all enhanced ionic conductivitytemperatures. Temperature itself plays a significant role, especially atthicker (but still thin) films.

Enhanced ionic conductivity in the sense of orders of magnitude greaterthan bulk ionic conduction for the above mentioned solid-stateelectrolytes is exhibited below a particular thickness, which may varyfrom material to material. As an example, the enhancement forelectrolytes in the zirconium family begins at below or about 700 nm.Thicker than that, bulk material characteristics dominate and thewell-known Arrhenius formula apply. In smaller thickness electrolytes,the enhanced ionic migration is observed and embodiments describedherein may make use of this advantageous property.

Temperature-dependent enhanced ionic conductivity is observed, inembodiments, when the interface conductance is greater than that of thebulk—that is, thinner than a threshold of about 700 nm. Invoking ambienttemperature performance requires films with acceptable ranges, forexample, lower than about 62 nm, in some embodiments. The range from 30nm to 1 nm may provide exceptional performance, with 1 nm providingnegligible resistance to ionic flow while still continuing electronholdoff.

Strained interfaces. Another technique for invoking enhanced ionicmigration involves a strained membrane or film. This may be achieved viadeposition of heterogeneous electrolyte materials in sandwiched form,such as perovskites/zirconium compounds/perovskites, or the reverseorder. Films of substantially less than 1 μm may be useful for achievingthe enhanced ionic migration in this way.

Advantageous aspects of the described energy storage devices include,but are not limited to:

-   -   A true, gel-free, solid-state energy storage device with solid        metal containing electrodes and solid electrolyte layers having        structural as well as electrical properties. The electrolyte        layers include glass or ceramic compositions capable of        supporting massive ionic migrations at the dimensions specified,        and at ambient or near ambient temperature.    -   Bi-layer electrodes capable of forming oxides and successions of        higher oxides in the presence of an electrical charge.    -   An elementary unit including a single cell comprised of two        electrodes and an electrolyte layer all of solid, consolidated        construction.    -   A structural energy storage device that is self-supporting and        requires no external case.    -   Methods of construction such as atomic layer deposition and        advanced commercial sputtering that permit full integration of        storage into integrated circuits.    -   An elementary unit consisting of two electrodes separated by        spacers or an open framework which is constructed on the        nano-scale and affords a volume for containing gaseous oxygen as        a source of ions.    -   A means of ionizing the confined oxygen.    -   A cell thickness of less than about 200 nanometers and as little        as about 30 nanometers and any intermediate value.    -   An electrode thickness of less than about 50 nanometers and more        than about 5 nanometers.    -   An electrolyte layer thickness of less than about 150 nanometers        and no less than about 20 nanometers.    -   A multi-layer construction ranging from 2 cells up to thousands        of cells and any number in between.    -   A multi-layer construction having any combination of series and        parallel connections between and among cells.    -   A modular design incorporating dispersed energy storage units.    -   A switching network for addressing dispersed energy storage        units.    -   A capability of undergoing full discharge without incurring        damage or degradation.    -   A formula that enables selection of appropriate electrode        materials based on a variety of factors including work function,        oxidation number, performance under various temperatures, and        availability.    -   A formula that enables the selection of appropriate solid        electrolyte materials based on factors including voids and/or        band gaps and membrane stress that permit ion migration through        the electrolyte, and performance under various temperatures.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

What is claimed is:
 1. A device, comprising: one or more integrated circuit components; and a Faradaic solid-state energy storage device comprising: a first electrode, wherein the first electrode has a first thickness, wherein the first thickness is greater than 1 nm and less than or equal to 80 nm, and wherein the first electrode comprises a first metal containing composition; a solid electrolyte positioned in direct contact with the first electrode, wherein the solid electrolyte has a second thickness, wherein the second thickness is greater than 1 nm and less than or equal to 500 nm, wherein the solid electrolyte comprises a solid-state material that selectively conducts ions at least at temperatures of between about 0° C. and about 100° C.; and a second electrode positioned in direct contact with the solid electrolyte, wherein the second electrode has a third thickness, wherein the third thickness is greater than 1 nm and less than or equal to 80 nm, and wherein the second electrode comprises a second metal containing composition; wherein the first electrode or the second electrode or both are directly or indirectly coupled to the one or more integrated circuit components.
 2. The device of claim 1, wherein the one or more integrated circuit components comprise one or more of a transistor, a central processor, a graphics processor, a memory unit, a semiconductor junction, or a photovoltaic cell.
 3. The device of claim 1, further comprising one or more switchable circuit components directly or indirectly electrically coupled to the first electrode or the second electrode or both.
 4. The device of claim 3, wherein the one or more switchable circuit components comprises a transistor or a relay.
 5. The device of claim 1, further comprising an inductive coupler or a planar inductor directly or indirectly electrically coupled to the first electrode or the second electrode or both.
 6. The device of claim 1, further comprising an energy distribution network directly or indirectly electrically coupled to one or more of the first electrode, the second electrode, or the one or more integrated circuit components.
 7. The device of claim 1, wherein the Faradaic solid-state energy storage device comprises a thin-film device directly integrated into one or more of the integrated circuit components.
 8. The device of claim 1, further comprising one or more additional Faradaic solid-state energy storage devices directly or indirectly electrically coupled to the one or more integrated circuit components.
 9. The device of claim 1, wherein the solid electrolyte has an amorphous structure.
 10. The device of claim 1, wherein the solid electrolyte has a crystal structure including vacancies that permit conduction or migration of ions through the crystal structure at temperatures of between about 0° C. and about 100° C.
 11. The device of claim 1, wherein the first metal containing composition and the second metal containing composition independently comprise Mn, Zn, Fe, Co, Ni, Cu, Mo, Tc, Ru, V, Bi, Ti, Rh, Pd, Ag, Au, W, Re, Os, La, Na, K, Rb, Cs, Ir, or Pt.
 12. The device of claim 1, wherein the first metal containing composition or the second metal containing composition independently comprises a metalloid including one or more of boron, silicon, germanium, arsenic, antimony, carbon, aluminum, or selenium.
 13. The device of claim 1, wherein the first metal containing composition or the second metal containing composition independently comprises oxygen, nitrogen, sulfur, a halogen, a non-lithium alkali metal, or hydrogen.
 14. The device of claim 1, wherein the ions comprise oxygen ions, nitrogen ions, sulfur ions, halide ions, non-lithium alkali metal ions, or hydrogen ions.
 15. The device of claim 1, wherein the solid electrolyte comprises a perovskite ceramic, a ceramic having a perovskite structure, a zirconium ceramic, a zirconium-scandia ceramic, a ceria-gadolinia ceramic, or an alumina ceramic.
 16. The device of claim 1, wherein the solid electrolyte comprises a multilayer structure comprising a plurality of different solid electrolyte layers.
 17. The device of claim 1, wherein the Faradaic solid-state energy storage device further comprises: one or more solid electrolyte and electrode bi-layers positioned in direct contact with the first electrode or the second electrode.
 18. The device of claim 1, wherein the first electrode, the solid electrolyte, and the second electrode are provided in an interdigitated configuration.
 19. The device of claim 1, wherein the Faradaic solid-state energy storage device and one or more of the integrated circuit components are arranged in a stacked configuration.
 20. The device of claim 1, wherein the Faradaic solid-state energy storage device and one or more of the integrated circuit components are arranged in a side-by-side configuration. 